Immunodominance in the T cell response to multiple non-H-2 histocompatibility antigens. IV. Partial tissue distribution and mapping of immunodominant antigens

The immunization of C57BL/6 responder mice with spleen cells from H-2-matched BALB.B donors, which differ by multiple non-H-2 histocompatibility (H) antigens, results in the generation of cytotoxic T lymphocytes (CTL) that are specific for only a limited number of immunodominant antigens. Previous analysis of the genes encoding these dominant antigens has not mapped these genes to any of the non-H-2 H loci defined by congenic strains. It would have been expected that the histogenetic techniques employed for congenic strain selection would have preferentially identified the "strongest" H antigens. Therefore, we have investigated the possibility that immunodominant antigens do not belong to the class of non-H-2 H antigens encoded by genes mapping to H loci defined and mapped by congenic strains. The first experiments were aimed at identifying antigens that were expressed by independently derived inbred strains and were cross-reactive with the immunodominant cytotoxic T cell target (CTT-1) antigen of BALB.B. Strong cross-reaction with the C3H.SW (H-2b) strain was observed; the C3H gene encoding this antigen was mapped with BXH recombinant inbred strains. Contrary to the mapping of the CTT-1 gene to chromosome 1 in BALB.B, the C3H gene was shown to map to either chromosome 4 or chromosome 7. This result indicates that identical, or at least extensively cross-reactive, non-H-2 antigens may be encoded by genes mapping to independently segregating loci in different inbred strains. The tissue distribution of immunodominant antigens was approached by determining the reactivity of CTL specific for these antigens with either lymphoid-derived or fibroblast-derived targets. These CTL effectively lysed lymphoblast and lymphoid tumor targets but did not lyse an SV40-transformed fibroblast line that was shown to be efficiently lysed by CTL specific for non-H-2 H antigens defined by congenic strains. Therefore, it was concluded that immunodominant antigens detected by B6 anti-BALB.B CTL have a restricted tissue distribution in comparison to non-H-2 H antigens defined by congenic strains. The implications of these results for our understanding of the origin and heterogeneity of non-H-2 cell-surface antigen recognized by effector T cells are discussed.     

Histochemical localization and analysis of blood group-related antigens in human pancreas using immunostaining with monoclonal antibodies and exoglycosidase digestion

We examined the distribution of blood group-related antigens using an indirect immunoperoxidase method with monoclonal antibodies (MAb) directed to A, B, H, Lewis a (Lea), Lewis b (Leb), Lewis x (Lex), and Lewis y (Ley) antigens and Type 1 precursor chain in human pancreas. Effects of prior digestion with exoglycosidases on MAb stainings were simultaneously investigated. A, B, H, Leb, and Ley antigens were detected in acinar cells and interlobular duct cells but not in centroacinar cells, intercalated duct cells, and islet of Langerhans cells. The expression of these antigens in acinar cells was not dependent on Lewis type and secretor status of the tissue donors, whereas that in interlobular duct cells was strictly dependent on secretor status. The distribution pattern of these antigens in acinar cells was not homogeneous, i.e., cells producing H antigens expressed both Leb and Ley antigens but not A or B antigens, whereas those producing A or B antigens did not secrete Leb and Ley as well as H antigens. Digestion with alpha-N-acetylgalactosaminidase or alpha-galactosidase resulted in the appearance of Leb and Ley antigens as well as H antigen in acinar cells producing A and/or B antigens. Type 1 precursor chain was not detected in pancreatic tissues from secretors but appeared in acinar cells producing H antigen after alpha-L-fucosidase digestion, which also disclosed Lex but not Lea antigen in acinar cells expressing both Leb and Ley. In some non-secretors, MAb against Type 1 precursor chain reacted with acinar cells without enzyme digestion. Although Lea antigen was not detected in acinar cells, it was found in centroacinar cells, intercalated duct cells, and interlobular duct cells from all individuals examined except two Le(a-b-) secretors. After sialidase digestion, Lex antigen appeared in centroacinar and intercalated duct cells from some individuals. Sialidase digestion also elicited reactivity with MAb against Type 1 precursor chain in islet of Langerhans cells from some individuals. These results demonstrate the complexity in the pattern of expression and regulation of blood group-related antigens in different cell types of human pancreas. Such complexity may largely be ascribed to differences in individual genotypes and in gene expression patterns of different cell types.     

Hemagglutinin (HA) proteins from H1 and H3 serotypes of influenza A viruses require different antigen designs for the induction of optimal protective antibody responses as studied by codon-optimized HA DNA vaccines

Effective antibody responses provide crucial immunity against influenza virus infection. The hemagglutinin (HA) protein is the major target of protective antibody responses induced by viral infection and by vaccination with both inactivated and live-attenuated flu vaccines, but knowledge about the optimal designs of protective HA antigens from different flu serotypes is still limited. In this study, we have significantly improved the immunogenicity of HA-expressing DNA vaccines by using codon-optimized HA sequences for either an H1 serotype (A/NewCal/20/99) or an H3 serotype (A/Panama/2007/99) human influenza A virus and then used these constructs as model antigens to identify the optimal HA antigen designs to elicit high-level protective antibody responses. Two forms of HA antigen, a wild-type, full-length HA and a secreted form with transmembrane (TM) domain-truncated HA, were produced. Both forms of HA DNA vaccines, from either H1 or H3 serotypes, were able to elicit high levels of HA-specific immunoglobulin G responses in immunized rabbits as measured by enzyme-linked immunosorbent assay. Interestingly, the abilities of H1 HA and H3 HA antigens to elicit hemagglutination inhibition (HI) and neutralizing antibody (NAb) responses differ. For the H1 HA antigens, the full-length HA induced significantly higher HI and NAb responses than did the TM-truncated HA. For the H3 HA antigen, both the full-length HA and TM-truncated HA induced high levels of HI and NAb responses. These data indicate that H1 and H3 antigens have different expression requirements for the induction of an optimal protective antibody response and that the structure integrity of HA antigens is critical for eliciting type-specific protective antibody responses. Our findings will have an important impact on future subunit-based flu vaccine development.     

The genetic origin of minor histocompatibility antigens

The purpose of this study was to elucidate the genetic origin of minor histocompatibility (H) antigens. Toward this end common inbred mouse strains, distinct subspecies, and species of the subgenus Mus were examined for expression of various minor H antigens. These antigens were encoded by the classical minor H loci H-3 and H-4 or by newly identified minor H antigens detected as a consequence of mutation. Both minor H antigens that stimulate MHC class I-restricted cytotoxic T cells (Tc) and antigens that stimulate MHC class II-restricted helper T cells (Th) were monitored. The results suggested that strains of distinct ancestry commonly express identical or cross-reactive antigens. Moreover, a correlation between the lack of expression of minor H antigens and ancestral heritage was observed. To address whether the antigens found on unrelated strains were allelic with the sensitizing minor H antigens or a consequence of antigen cross-reactivity, classical genetic segregation analysis was carried out. Even in distinct subspecies and species, the minor H antigens always mapped to the site of the appropriate minor H locus. Together the results suggest: 1 minor H antigen sequences are evolutionarily stable in that their pace of antigenic change is slow enough to predate subspeciation and speciation; 2 the minor H antigens originated in the inbred strains as a consequence of a rare polymorphism or loss mutation carried in a founder mouse stock that caused the mouse to percieve the wild-type protein as foreign; 3 there is a remarkable lack of antigenic cross-reactivity between the defined minor H antigens and other products.     

Distribution of H type 1-4 chains of the ABO(H) system in different cell types of human respiratory epithelium.

We used three anti-H monoclonal antibodies (MAbs) specific for H Type 1, H Type 2, and H Type 3/4 antigens to investigate the distribution of H Type 1-H Type 4 chains of the ABO(H) histo-blood group in the human respiratory system. Strong staining of H Type 1 chain and weak staining of H Type 2 chain were observed in mucous cells of submucosal glands of bronchial epithelium, which were dependent on the secretor status. No H Type 3/4 chains were detected in mucous cells. Serous cells of submucosal glands of respiratory system showed no staining by three anti-H antibodies. H Type 1 and H Type 3/4 antigens were detected heterogeneously in apical surfaces of bronchial epithelium from secretors but not from nonsecretors. In contrast, basal cells of bronchial epithelium expressed H Type 2 irrespective of the secretor status, probably regulated by the H gene. Some alveolar Type II cells contained only H Types 3/4, which were dependent on the secretor status, whereas alveolar Type I cells had no H antigens. Our results indicated that different cell types in respiratory epithelium expressed different types of carbohydrate chains of histo-blood group antigens under the control of the H or the Se gene.     

Immunogenicity of a non-class I MHC expressing murine tumor transfected with the influenza virus hemagglutinin or murine interleukin-2 genes

Summary The transfection of murine SP1 tumor cells with the hemagglutinin (HA) gene of influenza virus results, after fluorescent-activated cell sorting (FACS), in the selection of high-HA-expressing cell lines called H4A and H4B. Both lines fail to grow in syngeneic animals at doses that result in 100% tumor take of non-transfected tumor cells. Both grow in immunosuppressed mice. SP1 and H4A or H4B cells express few class I major histocompatibility complex (MHC) antigens but do express class II IA^k antigens. H4A or H4B cells engender a cytotoxic T lymphocyte (CTL) response but cannot protect against a challenge with SP1 cells. This CTL response is inhibited by anti-CD4 but not anti-CD8 antibodies. Using FACS, we were able to select a population (called H5AK5) with high class-I MHC antigen expression. Like H4A and H4B, H5AK5 cells fail to grow in syngeneic animals but do grow in immunosuppressed mice. However, unlike H4A or H4B, H5AK5 can induce protection against a challenge with 1 × 10⁵ SP1 cells. These studies indicate that the immunogenicity ofHA-transfected SP1 cells may correlate with the cell-surface expression of class II MHC antigens. However, HA-expressing SP1 cells seem able to induce a protective response against a parent SP1 cell challenge only if they also express class I MHC antigens. This view is supported by the observations that SP1 cells expressing murine interleukin-2 do not express class I MHC antigens, fail to grow in syngeneic animals, do grow in immunosuppressed mice but do not protect against a challenge with parental SP1 cells.This work was supported by The Clayton Fund, The Sid W. Richardson Foundation and PHS grants CA 39853 and 41525. Toshiyuki Itaya is a visiting scientist supported by the Smith Education Fund of the Department of Cell Biology. Troy Fiesinger is a summer research investigator sponsored by The University of Texas M. D. Anderson Cancer Center Summer Program for College Students     

Somatic and flagellar antigens ofSerratia ficaria from the United States and the Mediterranean region

Somatic (O) and flagellar (H) antigens of 37Serratia ficaria strains were studied. All strains shared a common H antigen (H1). Four O antigens were identified that defined four serovars (O1:H1, O2:H1, O3:H1, and O4:H1). All American strains studied (isolated from the fig-fig wasp biological cycle or from a human patient) belonged to serotype O1:H1. Strains from the Mediterranean region (Sicily, Tunisia, France) were not so antigenically uniform and all four serotypes were found in figs from Sicily.     

Replication and pathogenesis of the pandemic (H1N1) 2009 influenza virus in mammalian models

This study aimed to characterize the replication and pathogenic properties of a Korean pandemic (H1N1) 2009 influenza virus isolate in ferrets and mice. Ferrets infected with A/Korea/01/2009 (H1N1) virus showed mild clinical signs. The virus replicated well in lungs and slightly in brains with no replication in any other organs. Severe bronchopneumonia and thickening of alveolar walls were detected in the lungs. Viral antigens were detected in the bronchiolar epithelial cells, in peribronchial glands with severe peribronchitis and in cells present in the alveoli. A/Korea/01/2009 (H1N1) virus-infected mice showed weight loss and pathological lung lesions including perivascular cuffing, interstitial pneumonia and alveolitis. The virus replicated highly in the lungs and slightly in the nasal tissues. Viral antigens were detected in bronchiolar epithelial cells, pneumocytes and interstitial macrophages. However, seasonal H1N1 influenza virus did not replicate in the lungs of ferrets, and viral antigens were not detected. Thus, this Korean pandemic (H1N1) 2009 isolate infected the lungs of ferrets and mice successfully and caused more pathological lesions than did the seasonal influenza virus.     

Novel blood group H glycolipid antigens exclusively expressed in blood group A and AB erythrocytes (type 3 chain H). I. Isolation and chemical characterization

A series of blood group H antigens reacting with monoclonal antibody MBrl has been found in human blood group A and AB erythrocytes, but not in O or B erythrocytes. These H antigens are clearly different from the globo-H structure (Fuc alpha 1----2Gal beta 1----3GalNAc beta 1----3Gal alpha 1----4Gal beta 1----4Glc beta 1----1Cer), which was previously isolated from O erythrocytes and is also reactive with the MBrl antibody. The new series of H antigens associated with blood group A has been characterized as having TLC mobilities which approximately coincide with those of H2, H3, and H4 glycolipids. One of these A-associated H antigens, having a similar TLC mobility as the H2 glycolipid, was isolated from A erythrocytes and was characterized by 1H NMR spectroscopy, methylation analysis, and enzymatic degradation as having the structure shown below: (formula, see text). The structure represents a precursor of the repetitive A epitope attached to type 2 chain, previously called type 3 chain A (Clausen, H., Levery, S. B., Nudelman, E., Tsuchiya, S., and Hakomori, S. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 1199-1203). This A-associated H structure is hereby called type 3 chain H.     

Interaction of perch fucolectin with Lewis antigens

Interaction of fucolectin of perch Perca fluviatilis (PFL) with a set of Lewis antigens was studied by monitoring changes in its tryptophan fluorescence. PFL bound Le(c) (H type 1)-pentasaccharide (Ka = 6.6 x 10(3) M(-1)) and H type 6-trisaccharide (Ka = 2.5 x 10(3) M(-1)); essentially weaker, with Le(b)-hexasaccharide (Ka = = 4.0 x 10(2) M(-1)); and failed to interact with Le(a)-, Le(x)-, and Le(d)-containing oligosaccharides. PFL belongs to a new type of the fucolectins recognizing H-disaccharide Fuc alpha1-2Gal within various antigens, including H type 1/2 and Le(b).     

Monoclonal Antibodies againstAntigens of Hydra vulgaris and Hydra oligactis

The goal of the study was to obtain a panel of monoclonal antibodies (MAb) against antigens of freshwater polyps of the genus Hydra. Hybrid mice F₁(Balb/c × SJL/J) were immunized with cell membrane fraction of H. vulgaris and three months later their splenocytes were fused with cultured mouse myeloma cells 653A. Testing of culture fluids in ELISA with immobilized H. vulgaris cells, 82 hybridomas producing MAb were revealed. Study of MAb specificity in ELISA with H. vulgaris and H. oligactis cells indicated that 22% of them recognized only H. vulgaris antigens. About 50% of MAb recognized equally antigens of the both species. The rest of MAb reacted with H. vulgaris and H. oligactis antigens to different degree. Eight hybridomas producing MAb of all three above groups were adapted for growth as ascitic tumors. The distribution of antigens binding these MAb was studied in indirect immunofluorescence on fixed polyps, living or fixed cells, and on paraffin- embedded sections. Among the best studied MAb, of the greatest interest were the following reagents. One of them (1A10) revealed an antigen on surface membranes of ectodermal epithelial cells of H. vulgaris. The second one (1G10) was specific of the antigen located in mesoglea and basal cytoplasmic areas of ectodermal and entodermal epithelial cells of the both hydra species. The MAb 4G3 interacted with cytoplasmic antigen of ectodermal epithelia-muscular cells of the both hydra species. MAb 4H1 revealed nematocytes in H. vulgaris and H. oligactis. The data obtained indicate that in two species of hydra the epitopes binding the same MAb might be located in cells of different types.     

Expression of histo-blood group antigens by lipopolysaccharides of Helicobacter pylori strains from asian hosts: the propensity to express type 1 blood-group antigens

Past studies have shown that the cell surface lipopolysaccharides (LPSs) of the ubiquitous human gastric pathogen Helicobacter pylori (a type 1 carcinogen) isolated from people residing in Europe and North America express predominantly type 2 Lewis x (Le(x)) and Le(y) epitopes and, infrequently, type 1 Le(a), Le(b), and Le(d) antigens. This production of Lewis blood-group structures by H. pylori LPSs, similar to those found in the surfaces of human gastric cells, allows the bacterium to mimic its human niche. In this study, LPSs of H.pylori strains extracted from patients living in China, Japan, and Singapore were chemically and serologically analyzed. When compared with Western H.pylori LPSs, these Asian strains showed a stronger tendency to produce type 1 blood groups. Of particular interest, and novel observations in H.pylori, the O-chain regions of strains F-58C and R-58A carried type 1 Le(a) without the presence of type 2 Le(x), strains R-7A and H607 were shown to have the capability of producing the type 1 blood group A antigen, and strains CA2, H507, and H428 expressed simultaneously the difucosyl isomeric antigens, type 1 Le(b) and type 2 Le(y). The apparent proclivity for the production of type 1 histo-blood group antigens in Asian H.pylori LPSs, as compared with Western strains, may be an adaptive evolutionary effect in that differences in the gastric cell surfaces of the respective hosts might be significantly dissimilar to select for the formation of different LPS structures on the resident H.pylori strain.     

Blood group antigen expression in medullary carcinoma of the thyroid. An immunohistochemical study on the occurrence of type 1 chain-derived antigens.

Using monoclonal antibodies (MoABs) against blood group determinants and related carbohydrate sequences, it is now possible to clarify their carcinoma-associated modulation at a molecular level. In the present study a panel of MoABs against different type 1 chain derived blood group antigens, comprising A, B, H type 1, Le(a), sialyl-Le(a) (CA 19-9), sialyl type 1 structure (CA 50), and Le(b) was used to investigate their immunoreactivity in 38 medullary carcinomas of the thyroid (MTC) and in normal thyroid tissue. The antigens were not expressed in normal follicular or C-cells but were expressed to a various extent in MTC. The studies revealed some characteristic anomalies in the frequency and patterns of tumor-associated antigen expression. The MoAB C 50 stained 32 of the 38 tumors, H type 1 (Le(d)) was demonstrated in 21 and the Le(b) antigen in 27. The Le(a)- and the A antigen were detected in 10 and 12 tumors and the B antigen in one. From the results some rules about the pathways for tumor-associated re-expression of these antigens can be deduced. Le(a) antigen expression was significantly correlated with the CA 50 and Le(b) antigens. The significant relation observed between A-, H1-, and Le(b) antigen formation in MTC suggests the existence of a carcinoma-associated fucosyltransferase committing the type 1 precursor chain along the H1-antigen pathway, and by further glycosylation to an A-, B-, or a Le(b) antigen. Comparative studies of tumor-associated H type 1 and H type 2 antigen expression revealed that H type 2 antigen synthesis was significantly related to a blood type 0 in the host. On the other hand, H1 antigen reactivity was independent of the AB0 blood type of the hosts and was also detected in H type 2 antigen-negative tumors. These findings support the proposal that even in tumor tissue, H antigen expression is still determined by the interaction of at least two different genes. Despite the occurrence of the precursor substance (CA 50) and the formation of the Le(a)- and Le(b) antigens, indicating the presence of a alpha 1,4-fucosyl-transferase (Lewis-enzyme), only two tumors showed the formation of CA 19-9. In conclusion, the investigations demonstrated the dominant re-expression of three type 1 chain-derived structures in MTC, namely H type 1, Le(b), and CA 50. These findings support the general concept demonstrated in other carcinomas, that fucosyl- and sialyltransferases are preferentially activated in MTC.(ABSTRACT TRUNCATED AT 400 WORDS)     

The humoral response of mouse spleen cells to two types of sheep erythrocytes. III. A new VH region marker.

It was previously shown that there is multigene control of the response of mouse spleen cells to two types of sheep erythrocytes (H and L). Discriminator strains of mice make a much higher response to extra antigens found only on H SRBC than to the shared antigens found on both types of erythrocyte. Non-discriminator strains respond only to the shared antigens, making a response as great as the discriminator response to the extra antigens. In this study we have shown that the response to the extra antigen(s) on H SRBC is under the genetic control of a gene(s) located in the VH region near or to the left of the A5a, alpha 1, 3-dextran and NP makers.     

Suppression of antibody responses in allogeneic mice by products of lymphoid tissue. II. Lack of antigenic specificity and immunogenetic requirements of allogeneic suppressive factor (ASF).

Mice were irradiated, infused with thymocytes and immunized with a variety of antigens, i.e., sheep or horse red blood cells (SRBC or HRBC), diphtheria toxoid (DT) or bovine gamma-globulin (BGG). The spleen cells (T.Spleen cells) were harvested 5 days later and cellfree extracts were prepared. The extracts contained an allogeneic suppressive factor (ASF) that was capable of inhibiting IgM antibody responses of allogeneic or semi-allogeneic unirradiated mice. ASF had to be injected within 24 hr of immunization to be effective and a single injection delayed, rather than abolished, the antibody response at the cellular level. However, daily injections of ASF resulted in persistent suppression of antibody response. ASF activity was antigen nonspecific, i.e., the antigen used to stimulate ASF production did not have to be the same as the antigen used to test for ASF activity. C3H T.Spleen extracts were even immunosuppressive when prepared by exposure to C3BF1 alloantigens only; such extracts suppressed antibody responses of C3BF1 and DBA/2 mice. C3H ASF was removed from extracts after incubation with C3BF1 spleen cells but not after incubation with C3H spleen cells. C3BF1 spleen cells which had been preincubated with C3H ASF were unable to generate antibody-forming cells upon transfer to irradiated C3BF1 host mice. This suggests that the ASF molecule may be or include receptors for alloantigens. The immunogenetic requirements for ASF activity were evaluated by injecting extracts from C3H, C57BL, C3BF and BALB/c T.Spleen cells into C3H, CBA, C57BL, BALB/c, DBA/2, A or C3H.A recipient mice. All extracts tested had ASF activity. However, all allogeneic recipients were not suppressed by the extract material. The suppressive activity of ASF seemed to require two (or more) antigenic differences between donors and recipients of extract material, an H-2K or I antigen difference and a second antigen difference, possibility Ig-1. In the limited numbers of strain combinations tested, T.Spleen extracts suppressed IgM antibody response only if exposed to H-2 and Ig-1 antigens, e.g., BALB/c (H-2d, Ig-1a) ASF suppressed A (H-2a, Ig-1e) but not C3H.A (H-2a, Ig-1a) or DBA/2 (H-2d, Ig-1c). Separate ASF molecules may react with separate antigens on the cell surface, i.e., with H-2 and gammaG2a. Alternatively, one ASF molecule may react with two structurally associated antigens. If the latter is correct, it is conceivable that the beta2-microglobulin which is non-covalently linked to the major component of H-2 molecules expresses allotypic antigens coded for by Ig-1 and beta2-microglobulin is one of the antigens recognized by ASF.     

T lymphocyte responses to non-H-2 histocompatibility antigens. I. Role of Ly-1+2+ T cells as cytotoxic effectors and requirement for Ly-1+2+ T cells for optimal generation of cytotoxic effectors

Cytotoxic effector T cells specific for non-H-2 histocompatibility (H) antigens were examined for phenotypic expression of lymphocyte differentiation (Ly) antigens. Virtually all H-Y-specific cytotoxic effectors generated in mixed lymphocyte culture were Ly-1+2+ T cells. H-3-specific effectors comprised both Ly-1+2+ and Ly-1-2+ T cells. However, cytotoxic effectors specific for multiple non-H-2 H antigens were predominantly Ly-1-2+ T cells. The optimal generation of H-Y- and H-3-specific effectors required Ly-1+2+ T cells; optimal generation of multiple non-H-2 H antigen-specific effectors required an interaction between Ly-1+2- and Ly-1-2+ T cells. These observations suggest that the identity of the target H antigen in part determines the Ly type of responsive T cells. Our observations suggest that 2 alternative pathways of T cell response exist for non-H-2 H antigens. The first pathway involves an interaction between Ly-1+2- helper T cells and Ly-1-2+ cytotoxic effector precursors. The 2nd pathway simply involves the response of Ly-1+2+ T cells proliferating and generating H antigen-specific cytotoxic effectors.     

New O and H antigens of the international antigenic scheme forPlesiomonas shigelloides

A revised update of the International antigenic scheme forPlesiomonas shigelloides is presented. Twenty-six new O (O77–O102) and 10 new H (H42–H50 and H1a1d) antigens have been described since 1994. The sources of antigens are mostly human clinical strains, isolates from warmblooded animals and a few environmental cultures.     

Genetics of a non-H-2 antigen that stimulates "unrestricted" helper T cells and MLR

The inheritance of antigens expressed by C3H/Tif B cells that stimulate MHC-unrestricted helper T cells from C3H/HeJ was investigated. F1 hybrids between C3H/HeJ and C3H/Tif and 39 C3H/HeJ X F1 backcross mice were characterized as to the ability of their spleen cells to stimulate a proliferative C3H/HeJ T helper cell response and to respond to helper cell activity by the development of polyclonal plaque-forming cell responses. Backcross progeny wee also typed for the following markers segregating in this cross: 1) Responsiveness to the B cell mitogen lipopolysaccharide (LPS); 2) LyM-1 allotype; 3) antigen(s) stimulating a primary non-H-2 MLR between these strains, previously ascribed to Mls locus differences, 4) expression of target antigens for cytotoxic T cells raised in the same strain combination. The antigen(s) recognized by helper cells and those stimulating primary MLR are controlled by autosomal gene(s) and segregate as a single trait. These antigens, however, are not encoded in genes linked to either the Lps or the Mls loci, and are not recognized by cytotoxic T cells raised in the same strain combination.     

IgG subclass responses in childhood Helicobacter pylori duodenal ulcer: evidence of T-helper cell type 2 responses

BACKGROUND: Duodenal ulcer in adults chronically infected with Helicobacter pylori is associated with a polarized T-helper cell type 1 (Th1) mucosal immune response, with a predominantly immunoglobulin G2 (IgG2) systemic specific response. It has been suggested that children colonized by H. pylori also produce a mucosal Th1 response, but there are few studies that have measured IgG subclass responses in children with duodenal ulcer. MATERIALS AND METHODS: Seven children with endoscopically proven duodenal ulcer and H. pylori infection and 18 children with biopsy proven H. pylori infection but no duodenal ulcer had relative concentrations of IgG subclass responses (IgGsc) against H. pylori antigens measured by ELISA. Eighteen IgG seropositive adults acted as controls. The range of antigens recognised by IgG1 and IgG2 subclass responses were investigated by Western blots. RESULTS: There were no differences in mean IgGsc responses between children with or without duodenal ulcer. Adults produced an IgG2 predominant response. Western blots showed no qualitative differences in antigens recognised by IgG1 or IgG2. CONCLUSION: Children with duodenal ulcer, in contrast to adults, produce an IgGsc response consistent with a mucosal Th2 response to H. pylori regardless of the presence of duodenal ulceration. This suggests that disease causation amongst children with H. pylori associated duodenal ulceration may not be dependant upon a mucosal Th1 biased response.     

Quantitative flow cytometric analysis of ABO red cell antigens.

A flow cytometry method has been employed to quantitatively compare the expression of A, B and H antigens on various red blood cells (RBC). The H substance was directly labelled by fluorescein-conjugated anti-H lectin and the A and B antigens by indirect staining first with monoclonal anti-A or anti-B antibodies followed by fluorescently, fluorescein (FITC) or phycoerythrin (PE), labelled anti-mouse immunoglobulin (Ig) antibodies. More than a ten-fold difference in cellular fluorescence intensity was found within each sample. Both the percentage and the mean fluorescence of the positive subpopulation for each antigen were determined. Each RBC population was characterized with respect to the expression of A, B or H antigen by a compound mean value that was the calculated product of these two parameters. The results demonstrated a reciprocal relationship between the compound means of A or B and H. The ratio of A/H or B/H was found to be most informative. Homozygotes for A or B had ratios of greater than 200 and greater than 30, respectively, while heterozygotes (AO or BO) had ratios of less than 5. This method could also distinguish between A1 and A2; RBC carrying the A1 phenotype (as determined by agglutination with anti-A1 lectin) showed a higher A/H ratio than those carrying A2. In contrast to the reciprocity in the expression of A (or B) and H found in RBC obtained from different individuals, a direct correlation was found in the expression of these antigens by individual cells within a given population.(ABSTRACT TRUNCATED AT 250 WORDS)