Genetic interaction between Non-MHC T- and B-cell alloantigens in response to rous sarcomas in chickens

Chickens of Regional Poultry Research Laboratory (RPRL) inbred line 6₃ regress sarcomas induced by Bryan high-titer Rous sarcoma virus to a greater extent than chickens of line RPRL 100, although these lines are identical for the major histocompatibility B complex. They differ, however, at three independent autosomal loci: Ly-4 and Th-1 determine the surface alloantigens of partly overlapping subsets of T lymphocytes, and Bu-1 determines a surface alloantigen of B lymphocytes. The association of genotypes at these loci with quantitative variation in their ability to regress Rous sarcomas was tested in segregating F₄ generation progeny derived from crosses of lines 100 and 6₃. The Ly-4 and Bu-1 genotypes showed association with Rous sarcoma regression, but the Th-1 genotype did not. Chickens of the Ly-4 ^a/Ly-4 ^a, Bu-1 ^b/Bu-1 ^b and Ly-4 ^b/Ly-4 ^b, Bu-1 ^a/Bu-1 ^a genotypes had a significantly higher regressor ability than the other two double homozygous genotypes. These results indicate that higher regression is associated with (1) interaction between the Ly-4 and Bu-1 loci, and (2) complementation between either the line 6 Ly-4 ^a allele and the line 100 Bu-1 ^b allele, or the line 100 Ly-4 ^b allele and the line 6 Bu-1 ^a allele.     

An immunohistochemical study on the postnatal development of rat nasal-associated lymphoid tissue (NALT)

Summary This study concerns the development of nasal-associated lymphoid tissue in the rat, using immuno- and enzyme-histochemical staining techniques on cryostat sections. Nasal-associated lymphoid tissue is present at birth as a small accumulation of mainly T lymphocytes and non-lymphoid cells; B cells are rare. Distinct areas of T and B cells appear at 10 days after birth; by that time high endothelial venules are also observed. Intra-epithelial lymphocytes are present, most of them being T-helper cells. ED1+ macrophages are seen throughout the tissue. The proportion of ED1+cells does not change during ontogeny. ED2+cells (tissue macrophages) are present predominantly at the border between the lymphoid tissue and the surrounding connective tissue, in all age-groups. ED3+mononuclear cells are scattered throughout the nasal-associated lymphoid tissue of young animals. Later on, the ED3+ cells migrate into the border-area between lymphoid and connective tissue. Ia+ non-lymphoid cells in the nasal lymphoid tissue increase in number during ontogeny. Only a few of them show acid phosphatase activity, indicating that the proportion of classical scavenger macrophages is low. Some of them may be antigen presenting (dendritic) cells. Ia+ dendritic cells also occur between the epithelial cells. Moreover, some epithelial cells express the Ia marker.     

Induction and functional characterization of class II MHC (Ia) antigens on murine keratinocytes

To induce Ia molecules on the surface of murine keratinocytes (KC), healthy mice were treated daily with i.p. injections of rIFN-gamma at a dose of 50,000 U/day for 6 days. This resulted in strong Ia expression by KC as determined by immunofluorescence of epidermal sheets or cell suspensions with anti-class II mAb. To obtain a population of Ia-bearing KC devoid of Langerhans cells, a method of depleting Langerhans cells from such suspensions was developed. Although Ia+ KC were unable to stimulate allogeneic T cells in a primary epidermal cell-lymphocyte reaction (less than 5% control), they did induce a proliferative response in an allospecific T cell line. Ia+ KC were unable to present native peptide molecules to class II restricted, Ag-specific T cell hybridomas. However, Ia+ KC were able to present a peptide fragment of pigeon cytochrome c to a hybridoma, suggesting that although these cells cannot process native protein Ag, they can present antigenic peptides. Ia+ (but not Ia-) KC also served as targets for class II restricted cytolytic T cell clones. These data indicate that the Ia expressed by KC is a functional molecule, and that Ia+ KC can participate in some immunologic reactions.     

Influenza viruses as lymphocyte mitogens. II. Role of I-E molecules in B cell mitogenesis by influenza A viruses of the H2 and H6 subtypes

Influenza A viruses of the H2 and H6 subtypes behave as T cell-independent B cell mitogens for lymphocytes from strains of mice that express the class II MHC glycoprotein I-E (Ia.7+ haplotypes). We have examined the role of I-E molecules in mitogenesis by these viruses. Lymphocytes from (Ia.7+ X Ia.7-)F1 hybrid strains that express lower levels of I-E antigen than homozygous Ia.7+ strains showed a level of response to H2 and H6 influenza viruses that was intermediate between the high response of the Ia.7+ parent and the low response of the Ia.7- parent. The mitogenic response of H-2k lymphocytes to these viruses was completely inhibited by low concentrations of anti-I-Ek monoclonal antibody that had no effect on B cell proliferation induced by LPS or by influenza A virus of the H3 subtype. Furthermore, incubation of H-2k spleen cells with high concentrations of H2 (but not H3) influenza viruses substantially inhibited the binding of radio-labeled anti-I-Ek, but not anti-I-Ak, monoclonal antibody. Cell mixing experiments indicated that expression of I-E by the B cells was critical to the mitogenic response, whereas I-E expression by accessory cells may not be necessary. The data support a model in which B cell mitogenesis by these viruses results from direct binding of the viruses to I-E molecules on B lymphocytes.     

Class II MHC-bearing keratinocytes induce antigen-specific unresponsiveness in hapten-specific Th1 clones

Previous studies of Ia+ keratinocytes (KC) indicated that they functioned poorly or not at all when utilized as accessory cells for T cell activation. When Ia+ KC were modified with trinitrobenzene sulfonic acid, these cells did not induce a proliferative response in the TNP-specific, 1-Ek-restricted Th1 clone SE-4 (less than 5% of control). Analysis of supernatants generated from SE-4 cells incubated with these non-stimulatory accessory cells revealed low levels of IL-3 and IFN-gamma, but an absence of IL-2, when compared with supernatants generated from SE-4 cells stimulated with TNP-modified cultured Langerhans' cells that contain high levels of all of these lymphokines. Incubation of SE-4 cells with TNP-modified Ia+, but not Ia- KC or FITC-modified Ia+ KC, resulted in unresponsiveness to subsequent stimulation with TNP-modified functional accessory cells. Blocking studies with anti-class II MHC mAb revealed that the induction of unresponsiveness by hapten-modified Ia+ KC was restricted to the I-Ek molecule. Thus, the Ag and MHC specificities of unresponsiveness induced by TNP-modified Ia+ KC were identical to those observed for the proliferation of this clone in response to TNP-modified functional accessory cells. These data indicate the existence of a naturally occurring population of Ia+ cells that, after hapten-modification, induce an unresponsive state instead of proliferation of T cells.     

The immunopathology of experimental allergic encephalomyelitis (EAE). III. Differential in situ expression of strain 13 Ia on endothelial and inflammatory cells of (strain 2 x strain 13)F1 guinea pigs with EAE

This study was undertaken to determine if there is differential expression of the relevant strain-specific Ia antigen on endothelial and parenchymal inflammatory cells in the central nervous systems (CNS) of guinea pigs (GP) with acute experimental allergic encephalomyelitis (EAE). Adult inbred GP were sensitized with GP spinal cord homogenate and complete Freund's adjuvant. Strain 13 GP and (2 x 13)F1 hybrids developed clinical disease within 2 to 3 wk after sensitization, whereas strain 2 GP did not, although all sensitized GP had CNS mononuclear inflammatory infiltrates. By using monoclonal antibodies to strain-specific and framework Ia epitopes with an immunoperoxidase technique, the distribution and amount of the strain 2 and strain 13 Ia were analyzed. Equivalent strain 2 and strain 13 Ia expression was found in normal tissues from F1 animals. Strain 2 and strain 13 GP sensitized for EAE had increased strain-specific Ia staining of CNS vessels and inflammatory cells over controls. However, F1 GP with EAE had markedly increased strain 13, but not strain 2, Ia on CNS parenchymal vessels and mononuclear inflammatory cells (p less than 0.001, for both). These results suggest for the first time that specific major histocompatibility complex gene products are selectively expressed on endothelial and inflammatory cells in situ in immune reactions in the target organ of individuals of heterogeneous immunogenetic composition.     

Cell lineage segregation during bursa of Fabricius ontogeny

The population dynamics of myeloid and lymphoid lineages during bursa of Fabricius ontogeny were analyzed by immunofluorescence by using two monoclonal antibodies (mAb). CL-1 mAb reacts with all chicken hemopoietic cells, except mature erythrocytes. L22 mAb reacts with bursa and bursa-derived lymphocytes, with a minor subset of macrophages and with some cells of the thymic medulla. The staining of embryonic bursas by these antibodies helps to distinguish between two different lineages of hemopoietic cells: CL-1+/L22+ cells represent B lymphocytes and a minor subset of macrophages, while CL-1+/L22- cells correspond to most of the macrophages and to the granulocytes, which disappear at the end of the embryonic life. CL-1+/L22- as well as CL-1+/L22+ cells were first observed outside the bursal rudiment. This indicates that there is a pre-bursal segregation between these two hemopoietic lineages and that two different kinds of precursors colonize the bursal rudiment at about the same time (day 9 for CL-1+/L22- cells and days 9 or 10 for CL-1+/L22+ cells). Moreover our data show that the colonization of the bursal epithelium by hemopoietic precursors is a two-step phenomenon. The first cells which enter belong to the CL-1+/L22- lineage, express Ia-like antigens at a high level, are dendritic in morphology, and represent cells of the macrophage/dendritic cell lineage. They are responsible for the formation of the epithelial bud which are then colonized by a small number of lymphoid precursors which belong to the CL-1+/L22+ lineage. Quail-chick bursa grafting experiments were also performed and the grafts were examined for CL-1 (restricted to chicken hemopoietic cells) and L22 reactivity. These observations confirmed our previous findings about the kinetics of the colonization of bursal rudiment by hemopoietic precursors and give support for a pre-bursal segregation between two hemopoietic pathways.     

Desferoxamine blocks IL 2 receptor expression on human T lymphocytes

Thymidine uptake by PHA-stimulated human lymphocytes is reduced in the presence of 100 microM or greater concentrations of the iron-chelating agent desferoxamine (DF). We assessed expression of IL 2 receptor, 4F2 and Ia antigens, IL 2 production, and cell cycle progression by blood mononuclear cells (MNC) stimulated by PHA in the presence or absence of DF to determine whether the lack of T cell proliferation was a manifestation of inhibition of an earlier activation event. Tac antigen expression on PHA-stimulated MNC was inhibited by DF throughout 8 days of culture, and those cells which were positive had a low density of Tac antigen as compared with controls without DF. Expression of other activation antigens, 4F2 and Ia, was not impaired by DF. The supernatants of the DF-containing and control cultures contained equivalent IL 2 activity, as measured on the HT-2 cell line. Cell cycle analysis of these cultures shows that the addition of DF at the beginning of culture blocks most cells from undergoing G0 to G1 transition, whereas later addition of DF arrests the progression of the T cell blasts through the cell cycle. Separation of cells cultured with PHA and DF into Tac+ and Tac- subsets showed that progression from G0 to G1 was restricted to the former subset. These results suggest that interference with IL 2 receptor expression might contribute to the block in mitogen-induced proliferation caused by DF.     

The immunopathology of experimental allergic encephalomyelitis. II. Endothelial cell Ia increases prior to inflammatory cell infiltration

Experimental allergic encephalomyelitis (EAE) is a T cell-mediated neuroimmunologic disease model characterized by meningeal and parenchymal mononuclear cell infiltrates (see preceding companion paper). Here we report enhanced staining for Ia in the central nervous system (CNS) microvasculature endothelium in acute EAE in adult strain 13 guinea pigs (GP) sensitized with GP spinal cord homogenate (SC) or with GP myelin basic protein (MBP) in complete Freund's adjuvant (CFA). Cryostat sections of CNS and other tissues were stained with two monoclonal antibodies, 5S2 and 22C4, to GP Ia determinants, and with polyclonal antibody to factor VIII-related antigen (VIII-RA) as an endothelial cell marker. Morphometric techniques were employed on immunoperoxidase counterstained and coded sections to determine the frequency of Ia+ vessels and cells. Rare (approximately 10% of VIII-RA+) vascular endothelial cells were Ia+ in the CNS of normal and CFA-sensitized controls. SC- or MBP-sensitized strain 13 GP sacrificed on day 7, before the onset of neurologic signs (pre-clinical), had no detectable CNS mononuclear cell infiltrates, but had increased (approximately 30% of VIII-RA+) endothelial cell Ia staining over controls (p less than 0.001). The endothelial Ia staining persisted (approximately 35% of VIII-RA+) in vessels as the animals developed paralysis. There were no differences in endothelial cell Ia between SC- and MBP-induced disease. EAE-resistant strain 2 GP sensitized with SC/CFA had no neurologic signs, and had fewer inflammatory foci than strain 13 GP with EAE, but had similar numbers of Ia+ endothelial cells. No differences in endothelial cell Ia staining were found in non-CNS tissues among any GP groups. In EAE, increased endothelial cell Ia is a pre-inflammatory, target organ-specific alteration that persists during inflammation. The findings suggest that in vivo modulation of endothelial cell Ia may be part of the local immune response. Endothelial cells may play a significant role, in antigen presentation or in promoting T cell migration, in the in situ immune response in the CNS.     

Responder strain-specific enhancement of endothelial and mononuclear cell Ia in delayed hypersensitivity reactions in (strain 2 X strain 13)F1 guinea pigs

This study was undertaken to test the hypothesis that preferential responder strain-specific Ia expression can be detected in delayed hypersensitivity (DH) skin reactions. Seven adult (strain 2 X strain 13)F1 and two strain 13 guinea pigs were sensitized with poly-L glutamic acid-lysine (GL), poly-L glutamic acid-tyrosine (GT), and bovine insulin in complete Freund's adjuvant, and were skin tested with GL, GT, PPD, bovine insulin, porcine insulin (which has the same B chain as bovine insulin), and saline. Strain 2 guinea pigs react with bovine insulin A chain, GL, and PPD but not with GT or the bovine insulin B chain, whereas strain 13 guinea pigs react with bovine insulin B chain, GT, and PPD but not with GL or bovine insulin A chain. The (2 X 13)F1 animals had positive DH responses to GT, GL, PPD, and bovine insulin. At 24 hr, areas of induration were measured and the test sites and draining lymph nodes were biopsied. Cryostat sections were stained with monoclonal antibodies to strain 2 Ia, strain 13 Ia, and Ia framework determinants with immunoperoxidase. Stained dermal and subdermal inflammatory cells and vessels were counted on coded slides. In GT tests, there was more staining of dermal and subdermal cells and vessels for strain 13 Ia than strain 2 Ia (p less than 0.02). In bovine insulin tests there was more staining of dermal cells and vessels for strain 13 than strain 2 Ia (p less than 0.05). In GL tests there was more staining on dermal vessels and subdermal cells and vessels of strain 2 Ia than strain 13 Ia (p less than 0.05). There was much greater staining of strain 2 Ia of dermal cells and vessels in GL tests compared with strain 2 Ia staining in GT and bovine insulin tests (p less than 0.02, cells; p less than 0.01, vessels). No significant differences between strain 2 and strain 13 Ia expression were found in PPD, porcine insulin tests, saline controls, or in lymph nodes that drained sensitization sites from animals in which GL and GT had been injected on different sides. Anti-Ia framework expression generally correlated with the greater parental strain Ia in each reaction. These findings and previous observations in experimental allergic encephalomyelitis suggest that responder type Ia may be selectively found in vivo on mononuclear and endothelial cells in sites of T cell-mediated hypersensitivity reactions.     

Differential regulation of class II MHC determinants on macrophages by IFN-gamma and IL-4

Initiation of an immune response depends upon expression of class II MHC determinants on plasma membranes of APC. Murine peritoneal macrophages treated with either rIFN-gamma or rIL-4 display significantly more class II MHC determinants than untreated control cells. Analysis of the induction of macrophage Ia Ag by these cytokines showed considerable quantitative and qualitative differences. Maximal levels of Ia Ag induced in macrophages and detected by ELISA after IL-4 treatment at 48 h was about 80% of that induced by IFN-gamma. However, the frequency of Ia+ cells in replicate macrophage populations cultured for 48 h in excess concentrations of cytokine was 60 to 80% with IFN-gamma, 30 to 40% with IL-4, and 5% with medium alone. Thus, the subpopulation of macrophages able to respond to IL-4 for induction of Ia Ag expression was less than that able to respond to IFN-gamma. Expression of Ia Ag on macrophages continuously exposed to IFN-gamma was maximal at 48 h and remained at this high level through 6 days. Maximal Ia Ag expression for IL-4-treated cells was also detected at 48 h, but was not sustained with time in culture, and returned to base line by 4 days. A similar time course for levels of Ia-specific message in macrophages at various times after IFN-gamma and IL-4 treatment was detected by Northern dot blot analysis. Loss of Ia mRNA and Ag with time in culture in the IL-4 treated cells was not due to macrophage cell death, depletion of active cytokine, or presence of fluid-phase inhibitors. IL-4 unresponsive cells were fully capable of maximal response to IFN-gamma for Ia Ag induction. These findings suggest that IL-4 and IFN-gamma induce class II MHC determinants through different mechanisms which may provide discrete regulatory control of APC function.     

Activated lymphocytes in patients with newly diagnosed type 1 (insulin-dependent) diabetes mellitus

The expression of activation antigens (transferrin receptor, IL-2 receptor and Ia antigen) on circulating T lymphocytes from Japanese children with Type 1 diabetes was studied using five monoclonal antibodies (Ab), OKT9, anti-Tac Ab, OKIa1, anti-human HLA-DR Ab and OKT3. For detecting Ia positive T cells, the dual staining technique using OKT3 and anti-Ia antibody was employed. Four out of six patients (67%) with newly diagnosed Type 1 diabetes showed a raised level of either OKT9 or Tac positive cells when examined at diagnosis. These patients, however, rapidly lost these activation antigens after the insulin therapy was started. In contrast, in 32 long-standing patients, only 2 (6%) had a high percentage of OKT9 positive cells and none of them demonstrated Tac positive cells. One out of six newly diagnosed patients or three out of 21 long-standing patients had a significantly high percentage of Ia-positive T cells compared with normal subjects. In poorly controlled long-standing patients whose HbA1 value was higher than 14%, none of them had an increased number of activated lymphocytes. Therefore, it is unlikely that insulin deficiency and hyperglycemia were responsible for the changes observed in these studies. Activated lymphocytes might be related to activation of the immune system involved in pathogenesis of Type 1 diabetes.     

The avian ChB6 alloantigen triggers apoptosis in a mammalian cell line

Many developing B lymphocytes are deleted by apoptosis. However, the mechanism signaling their demise remains poorly understood. Like mammals, chicken B cells are selected during their development; >95% of the cells in the bursa of Fabricius die without entering the secondary immune system. The molecule chB6 (Bu-1) has been used as a marker to identify B cells in the chicken. ChB6 is a type I transmembrane glycoprotein whose function is enigmatic. We have provided evidence that chB6 can induce a rapid form of cell death exhibiting characteristics of apoptosis. Here we further examine cell death induced by chB6 in a transfected mouse cell line. ChB6 is shown to cause apoptosis in this cell line as detected by a TUNEL assay for DNA fragmentation. This apoptosis is subject to regulation by signals from growth factor or by Bcl-x(L). Furthermore, we show that Ab binding to chB6 leads to cleavage of caspase 8, caspase 3, and poly(ADP ribose) polymerase. Overall, these data support the hypothesis that chB6 is a novel death receptor on avian B cells.     

The Mechanism of Environmental Endocrine Disruptors (DEHP) Induces Epigenetic Transgenerational Inheritance of Cryptorchidism

Discussion on the role of DEHP in the critical period of gonadal development in pregnant rats (F0), studied the evolution of F1-F4 generation of inter-generational inheritance of cryptorchidism and the alteration of DNA methylation levels in testis. Pregnant SD rats were randomly divided into two groups: normal control group and DEHP experimental group. From pregnancy 7d to 19d, experimental group was sustained to gavage DEHP 750mg/kg bw/day, observed the incidence of cryptorchidism in offspring and examined the pregnancy rate of female rats through mating experiments. Continuous recording the rat’s weight and AGD value, after maturation (PND80) recording testis and epididymis’ size and weight, detected the sperm number and quality. Subsequently, we examined the evolution morphological changes of testicular tissue for 4 generation rats by HE staining and Western Blot. Completed the MeDIP-sequencing analysis of 6 samples (F1 generation, F4 generation and Control). DEHP successfully induced cryptorchidism occurrence in offspring during pregnancy. The incidence of cryptorchidism in F1 was 30%, in F2 was 12.5%, and there was no cryptorchidism coming up in F3 and F4. Mating experiment shows conception rate 50% in F1, F2 generation was 75%, the F3 and F4 generation were 100%. HE staining showed that the seminiferous epithelium of F1 generation was atrophy and with a few spermatogenic cell, F2 generation had improved, F3 and F4 generation were tend to be normal. The DNA methyltransferase expression was up-regulated with the increase of generations by Real Time-PCR, immunohistochemistry and Western Blot. MeDIP-seq Data Analysis Results show many differentially methylated DNA sequences between F1 and F4. DEHP damage male reproductive function in rats, affect expression of DNA methyltransferase enzyme, which in turn leads to genomic imprinting methylation pattern changes and passed on to the next generation, so that the offspring of male reproductive system critical role in the development of imprinted genes imbalances, and eventually lead to producing offspring cryptorchidism. This may be an important mechanism of reproductive system damage.     

Appearance of Extrachromosomal Circular DNA in Lymphocytes from Developing Chick Bursa

Lymphocytes were purified from the developing bursa of Fabricius of chick embryos and chickens and pressed with a mica sheet. Then the extruded DNA complexes were adsorbed to the mica and processed for electron microscopy. Circular DNA complexes were found at 40 to 60 copies in all bursal lymphocyte except 12-day-old embryonic bursas, which contained 150 copies. Circular DNA complexes of more than 1 μm (larger circular DNA) appeared in 12-day-old embryonic bursas at more than 20 copies per cell, and subsequently decreased in number to less than 10 copies per cell. These changes in the size distribution and copy number of circular DNA coincided with lymphocyte differentiation of the hemopoietic precursor cells in the bursa after seeding.     

Distribution of histopathology and Ia positive cells in actively induced and passively transferred experimental autoimmune orchitis

Histopathology in testes from mice with actively induced experimental orchitis (EAO) (active EAO) and those from recipients of testis-sensitized lymphocytes (passive EAO) had different distributions. In passive EAO, maximum orchitis existed in the straight tubules, rete testis, and ductus efferentes, obstruction of which led to extreme dilatation of seminiferous tubules. Unusual intralymphatic granulomata also resulted in dilated testicular lymphatics. In active EAO, maximum orchitis affected seminiferous tubules under the testicular capsule, away from the rete testes. Vasitis was common and occurred in both active and passive EAO. In normal testes, IA+ F4/80+ cells were sparse but formed a cuff around the straight tubules. After immunization with testis in adjuvant or with adjuvant alone, the number, size, and staining intensity of IA+ cells increased dramatically beginning on day 5, 7 days before disease onset. Simultaneously, epithelial cells confined to the ductus efferentes became Ia+. Although recipients of sensitized lymphocytes also developed epithelial Ia in the ductus efferentes, they did not show changes in testicular interstitial Ia+ cells. Our findings indicate that testicular autoantigens are not completely sequestered, but are accessible to and can react with passively transferred immune lymphocytes in well-defined regions of the germ cell compartment. These regions coincided to a large extent with maximum expression of periductal or epithelial Ia. Changes in Ia+ cells in the testis, which are inducible by adjuvants and precede orchitis, may account in part for the different distribution of histopathology of active EAO.     

Effects of estradiol on the development of the bursa of Fabricius in Japanese quail

Effects of androgens on the development of the bursa of Fabricius are better understood than those of estradiol, despite the known sensitivity of the bursa to estradiol early in embryogenesis. The goal of this study was to determine the effects of one-time yolk injections of estradiol at day 4 of incubation on the development of the bursa and spleen as indices of treatment effects on the immune system. Follicle size and numbers in hatchling bursas were significantly reduced at 50 and 500 microg/egg, respectively. Additionally, distorted plicae and thicker epithelial layers surrounding the plicae were observed in day-old chicks at the same treatment levels. Adult bursas from birds embryonically exposed to estrogen were significantly larger than controls, suggesting an inhibition of natural bursal regression. Although estradiol altered the development of the bursa, the spleen appeared to be unaffected. The observed effects of estradiol on the development of the bursa indicate that this lymphoid organ may be a target for developmental disruption by estrogenic endocrine disrupting chemicals, though long-term consequences of embryonic exposure on immune function remain unknown.     

The localization of macrophage subsets and dendritic cells in the gastrointestinal tract of the mouse with special reference to the presence of high endothelial venules

Summary This study concerns the distribution of macrophages and dendritic cells (DC) in the gastrointestinal tract of the mouse. Heterogeneity of macrophage population was found by using the MOMA-1, MOMA-2, ERTR-9, Mac-1 and F4/80 monoclonal antibodies. MOMA-1, ERTR-9, Mac-1 and F4/80+ cells were detected mostly at the villous cores in the lamina propria of the villi, whereas MOMA-2+ cells were primarily found around the crypts at the base of the villi. These MOMA-2+ cells revealed a granular appearance throughout the cytoplasm and displayed a strong acid phosphatase (AcPh) activity. Few MOMA-2+ cells were seen at the top of the villi in the epithelium. Although MOMA-1 and ERTR-9+ cells have similar morphology and the same distribution patterns in the lamina propria, they are likely different populations, because in Peyer's patches (PP), MOMA-1+ cells were present, whereas ERTR-9+ cells could not be detected. Both populations displayed AcPh activity. Strongly stained Mac-1+ cells were abundantly seen in the lamina propria of the small intestine. F4/80+ cells were rare. NLDC-145+ cells with AcPh activity and weak Ia staining were also found. In the PP-associated villi and in the T-dependent area of PP, dendritic NLDC-145+ cells, which were strongly Ia positive, were detected. MIDC-8+ cells were found only in the T-dependent area. Few NLDC-145+ cells (dendritic cells) were found in the upper part of the oesophagus. These cells were also stained with the MIDC-8 antibody. The MECA-325 monoclonal antibody recognized high endothelial venules (HEV) in PP and blood vessels at the base of the villi of the jejunumileum and caecum. Unlike in PP, the endothelium of the venules in the villi was flat.     

Subpopulations of mouse Lyt-2+ T cells defined by the expression of an Ly-6-linked antigen, B4B2

The production and characterization of a rat mu,kappa monoclonal anti-mouse T cell subset antibody, B4B2, is reported in this paper. B4B2 typing of lymphoid tissues of commonly used inbred mouse strains revealed two types of reactivity patterns. They can be characterized as C57BL/6-like (B6-like) or C3H/He-like (C3H-like). Among B6-like strains, B4B2 recognizes 5 to 10% of spleen cells, 30 to 50% of bone marrow cells, and less than 2 to 3% of thymocytes. In C3H-like strains, B4B2 reacts with less than 1% of spleen cells, 2 to 8% of bone marrow cells, and less than 1% of thymocytes. B4B2 recognizes a T cell subset differentiation antigen expressed by B6-like strains but not by C3H-like strains. Typing of BXH recombinant inbred strains showed linked expression of B4B2 and the Ly-6 antigen. The expression of B4B2 antigen appears to be under codominant control as the median fluorescence distribution of B4B2+ cells in C57BL/6 was approximately twice that of (C57BL/6xC3H)F1. B4B2 was shown to react with approximately 40 to 50% of Lyt-2+ T cells and less than 1% of L3T4+ T cells. No staining of resting or activated B cells by B4B2 was detected. The ratio of B4B2+:Lyt-2+ cells was similar for resting T cells and activated T cells obtained from mitogen-stimulated cultures or mixed lymphocyte cultures. In neonatal spleen, substantially more B4B2+ than Lyt-2+ cells were found. With increasing age, however, a rapid decline in B4B2+ cells and a corresponding increase of Lyt-2+ cells was observed. By approximately 1 mo of age, the relative proportion of these subsets had reversed so that Lyt-2+ cells became more numerous than B4B2+ cells.