Mapping immunodominant antigens and H-2-linked antibody responses in mice urogenitally infected with Chlamydia muridarum

To identify immunodominant antigens and MHC-restricted antibody responses, seven different strains of mice were intravaginally infected with Chlamydia muridarum and compared for antibody responses to 257 C. muridarum proteins. The 7 strains of mice recognized a total of 109 proteins as antigens, of which, 5 antigens (TC0660, TC0727, TC0828, TC0726 & TC0268) were each recognized by 60% or more mice from each mouse strain and thus designated as immunodominant antigens. Furthermore, antibody responses to 19 other antigens displayed strong associations with mouse H-2 haplotypes, including 6 antigens (TC0480, TC0912, TC0229, TCA04, TC0289 & TC0892) whose antibody responses were linked to H-2(b), 8 (TC0035, TC0387, TC0052, TC0781, TC0373, TC0117, TC0066 & TC0396) to H-2(d) and 5 (TC0512, TC0177, TC0589, TC0794 & TC0596) to H-2(k) haplotypes respectively. Interestingly, H-2(b) was negatively associated with antibody responses to most of the antigens that were positively linked to H-2(d) or H-2(k) haplotypes. These results by mapping Chlamydia trachomatis antigens commonly recognized by mice with different strain background and H-2 genes and revealing antigen association with H-2 haplotypes have provided important information for developing chlamydial subunit vaccines and understanding chlamydial pathogenesis.     

Expression of H-2Dd and H-2Ld mouse major histocompatibility antigen genes in L cells after DNA-mediated gene transfer

Among the more than 20 H-2-like genes in the BALB/c mouse genome, there are two classical transplantation antigens (H-2Dd and H-2Ld) encoded at the D-end of the major histocompatibility complex. Here we report the identification of a bacteriophage clone that encodes H-2Dd. The H-2Dd gene was identified by nucleotide sequence analysis and by characterization of the new H-2 antigen expressed when the cloned gene was introduced into mouse L cells by DNA-mediated gene transfer. The previously identified H-2Ld gene was then compared with the H-2Dd gene. The two genes appear to have the same general structure, and for the 854 nucleotides that have been compared, the two genes are 89% homologous. The H-2Ld and H-2Dd antigens expressed on mouse L cells after DNA-mediated gene transfer were examined by immunologic criteria. The stably transformed cell lines express apparently normal levels of H-2Dd and H-2Ld on the cell surface as measured by quantitative immunofluorescence by using monoclonal anti-H-2 antibodies. They synthesize H-2Dd and H-2Ld at normal rates as determined by endogenous labeling and immunoprecipitation of cell extracts. They evoke a strong specific serologic response when used to immunize C3H mice. The newly expressed antigens are able to serve as targets for alloreactive T cells. These cloned genes provide good substrates for examining the evolution of two closely linked H-2 antigen genes. Comparison of the structures of these genes provides clues to the basis for the differential expression of these antigens and their different biologic functions.     

Localization of H-2Kk in developing mouse teeth using monoclonal antibody

The in situ distribution of H-2 antigens during mouse tooth morphogenesis was investigated using monoclonal antibodies to H-2Kk and indirect immunofluorescent techniques. H-2 antigens were detected in the basement membrane region of fetal molars; they were absent from both the epithelial and dental mesenchyme. H-2 antigens were not found in newborn and 4-day-old mouse molars.     

Synthesis of H-2 antigens by preimplantation mouse embryos

An enzyme-linked immunosorbent assay (ELISA), which utilized anti-H-2 monoclonal antibody, was used to detect H-2 antigens on preimplantation mouse embryos. All embryonic stages studied, including unfertilized eggs and 1-cell, 2-cell, 8-cell, and blastocyst-stage embryos, showed the presence of H-2 antigens. To prove that the H-2 antigens were not cytophilically adsorbed to the embryos, blastocysts were treated with papain to strip off the H-2 antigens, and then the embryos were further incubated to allow the H-2 antigens to regenerate. After a 3-h incubation time, 60% of the H-2 antigens on the embryos had reappeared, proving that the H-2 antigens were synthesized by the embryos themselves.     

Does the major histocompatibility complex serve as a specific receptor for Semliki Forest virus?

Murine F9 and PCC4 teratoma cells do not express H-2 major transplantation antigens according to virus-specific T-lymphocyte cytotoxic or serological assays. However, such cells can be infected with and readily replicate many types of viruses (coxsackie B 3, mouse hepatitis, Sindbis, Semliki Forest [SFV], lymphocytic choriomeningitis, Pichinde, vesicular stomatitis, herpes simplex type 1) to the same extent as do murine F12 teratoma cells and mouse embryo fibroblasts, all of which express the H-2 determinants. In contrast, F9 and PCC4 cells are not productively infected with murine cytomegalovirus, whereas F12 and mouse embryo fibroblast cells are. In addition to replicating in H-2-negative murine teratoma cells, SFV replicates in H-2-negative murine lymphoblastoid cells. The ability of SFV to infect cells without H-2 antigens and then to effect viral antigenic expression in the cells' cytoplasm and on their surface with similar kinetics and in equivalent amounts as cells with H-2 antigens indicates that the H-2 receptor is not needed for SFV infection. Daudi cells, which lack HLA antigens, block the replication of SFV. This occurs at some point after receptor binding, as demonstrated by diminished viral mRNA. In addition, a possible membrane defect precludes viral exit in Daudi cells transfected with SFV infectious RNA. These results indicate that a cell's possession of H-2 antigens is not a requirement for SFV infection and that major histocompatibility complex antigens are not specific receptors for this virus.     

F1 hybrid-anti-parental H-2b cell-mediated lympholysis: genetic control of target antigens by the H-2D region

The immunogenetic specificity of (C57BL/6 X DBA/2)F1 anti-parental C57BL/6 cytotoxic T lymphocytes (CTL) induced in primary mixed spleen cell cultures was determined in direct lytic and competitive inhibition assays. A large panel of peritoneal exudate cells (PEC) bearing nonrecombinant and recombinant H-2-Tla haplotypes was the source of target and inhibitor cells. All PEC of H-2b, H-2bc, H-2j, and H-2ja types, irrespective of background genetic constitution, were as susceptible to direct lysis as C57BL/6 PEC, but PEC of H-2a, H-2d, H-2k, H-2q, H-2s, and H-2u types were not. The possible involvement of the Tla region in controlling target antigens was excluded by testing PEC obtained from 4 H-2/Tla or intra-Tla recombinant mouse strains. The genes controlling target antigens were mapped to the D region with the aid of 9 intra-H-2 recombinants; for target PEC to be lysed it was necessary and sufficient that Db antigens be part of the H-2 phenotype. These results were confirmed by competitive inhibition assays. Resident peritoneal cells not exposed to fetal bovine serum were also lysed by F1 anti-parental H-2b CTL, a demonstration that target antigens are expressed on normal cells.     

Association of mouse adenovirus-induced cell surface antigen(s) with histocompatibility antigens

The topological relationship on the mouse adenovirus (M-Ad)-infected cell surface between virus-induced specific cell surface(s) antigens and serologically defined major histocompatibility antigens (H-2) was analyzed by the cap formation technique. Rhodamine-isothiocyanate (RITC)-labeled anti-S serum failed to stain the surface of virus-infected lymphoid cells which were pretreated with anti-H-2 serum and fluorescein isothiocyanate (FITC)-labeled anti-mouse immunoglobulin serum (anti-M-Ig) to cap the appropriate H-2 antigens. Conversely, the capping of the S antigens by pretreatment with anti-S followed by FITC anti-M-Ig serum induced cocapping of H-2 antigens. The β₂ microglobulins (β₂m) were also shown to be cocapped with S antigens by anti-β₂m or by anti-S serum. The S antigens, however, did not cocap with mouse-immunoglobulins or Thyl. 2 antigens on virus-infected B or T lymphocytes, respectively. To further elucidate the molecular relationship between S and H-2 antigens, radio-iodinated virus-infected cells were solubilized with Nonidet P40 (NP40) and S antigens were precipitated with anti-S serum. When the precipitates were analysed with sodium dodecyl sulfate Polyacrylamide gel electrophoresis, two major peaks were seen at positions of molecules of about 45,000 and 12,000 daltons both of which corresponded with molecules which were observed when NP40 extracts of virus-infected or uninfected cells were precipitated with anti-H-2 serum. Sequential immunoprecipitation analysis of infected cell extracts showed that S antigens were coprecipitated with either H-2K or H-2D antigens. These results suggest that the S antigens are somehow associated with H-2K or H-2D antigens separately.     

Demonstration of H-2 antigens on preimplantation mouse embryos using conventional antisera and monoclonal antibody

Mouse embryos at the 2-cell, 8-cell, and blastocyst stages of development were examined for the presence of H-2 antigens by immunoperoxidase labeling and transmission electron microscopy. Conventional antisera made in congenic mouse strains were used to study embryos of four different haplotypes: b, a, k, and d. Blastocysts showed uniform heavy labeling of all cells of the trophectoderm, 8-cell embryos showed lighter labeling of only some of the cells, and 2-cell embryos showed no labeling. Similar results were found for all four haplotypes studied. In addition, monoclonal antibody 11-4.1 (anti-Kk) was reacted with homologous (H-2k) and heterologous (H-2b) blastocysts. Positive results with the monoclonal antibody corroborates the concept that H-2 antigens are expressed on early mouse embryos.     

Close Association of Virus-Specific Cell Surface (S) and H-2 Antigens in Ad12-Infected and -Transformed Mouse Cells

A virus-specific cell surface (S) antigen in adenovirus type 12 (Ad12)-transformed mouse cells has been assumed to be a direct target for cytotoxic thymus-derived lymphocytes (CTL). In this study, the spatial proximity between the S and H-2 antigens was determined by three different methods, the proximity and co-capping tests, and the test for blocking of CTL-mediated lysis by anti-H-2 serum. In the proximity test with Ad12-infected thymic and splenic lymphocytes, and an Ad12-transformed line of C3H/He (H-2^k) mouse cells, anti-H-2^k and anti-S sera reciprocally inhibited fluorescent-antibody staining of the opposite antigens. By contrast, anti-Thy-1, 2 serum as well as anti-Ia and anti-Ig sera failed to show any appreciable effect in this test, when paired with anti-S serum. In addition, the S and H-2 antigens co-capped in the infected thymic lymphocytes, and CTL-mediated lysis of the transformed cells was abrogated equally by treatment of cells with anti-S and anti-H-2 sera. These results clearly demonstrate that there is a close proximity between the S and H-2 antigens on the surface of Ad12-infected and -transformed mouse cells.     

Aberrancy in immunogenicity and cell-surface expression of H-2 antigens on erythrocytes

Immunogenicity for T cell-independent B-cell response assessed by splenic plaque-forming cell (PFC) response and cell-surface expression measured by laser flow cytometry of various class I H-2 antigens on mouse red blood cells (RBC) were compared. It was found that the order of magnitude of both immunogenicity and cell-surface expression on RBC is H-2D^d H-2D^b > H-2K^d, H-2K^b. Furthermore, H-2^d public antigens and H-2L^d antigens were neither immunogenic nor easily demonstrable on RBC. These findings contrasted with poor immunogenicity for PFC response (Nakashima et al. 1982, 1983) and proportionally strong expression of H-2 antigens on lymphoid cells. Immunogenicity and cell-surface expression of H-2D^d antigen on RBC were not shown to be controlled by the action of genes outside H-2D. It was therefore suggested that a number of H-2 antigens, including H-2K^d private, H-2K^b private, and H-2^d public specificities are at least functionally defective on RBC. This is possibly due to the structural characteristics of the antigens. Since immunogenicity and cell-surface expression were in parallel, the expression of H-2 antigens on RBC must be dictated by a subset of B cells whose activity was assessed by PFC response. This finding supports the view that the H-2 molecules display a new category of activity which is different from their ability to activate T cells and depends on their expression on RBC.     

The production of Non-H-2 histocompatibility alloantibodies in the mouse

Alloantibodies specific for non-H-2 histocompatibility antigens of the mouse have been produced. Immunization (BALB/cJ×DBA/2J)F₁ anti-B10.D2/n was conducted, followed by hemagglutination, immunofluorescence, and mixed hemabsorption tests on absorbed and unabsorbed sera. The results indicate that antibodies specific for H-3^a and H-8^a antigens are present. In addition, H-8^a antigenic determinants were detected on erythrocyte membrane surfaces, as well as on cells of other body tissues.     

Anti-major histocompatibility complex immunity detected prior to intentional alloimmunization. II. Monoclonal H-2-specific antibodies obtained from an unimmunized C57BL/KaLwRij (H-2b) mouse

A monoclonal 'natural' anti-H-2 IgM antibody produced by a hybridoma cell line OL-3.17 (H-2 m. 209) is described. The OL-3.17 monoclonal antibody was obtained by hybridization of spleen B cells from an unimmunized C57BL/Ka (H-2b) mouse in the serum of which simultaneously an IgM kappa paraprotein of high concentration and a natural H-2-specific antibody of high titer was detected. The monoclonal antibody OL-3.17 reacted strongly with H-2d and H-2s and weakly with H-2k,q,r lymphocytes, thereby detecting a hitherto unknown H-2 public determinant. The target molecules for OL-3.17 cocapped with class-I H-2 antigens, but immunoprecipitation of H-2 antigens was not achieved. This is the first monoclonal H-2-specific antibody obtained from a mouse without intentional immunization and, with high probability, was derived from a B-cell clone which produced natural H-2-specific antibodies detectable in the serum of the original mouse.     

Intraspecies identification of cultured murine cells by using H-2 antigen typing

17 mouse cell lines have been screened with specific sera against H-2 antigens. All the cell lines tested expressed H-2 antigens characteristic of the donor haplotype. The data obtained indicate that H-2 typing of cultured mouse cells can be used as an approach to control their intraspecies diversity.     

Lateral diffusion and patch formation of H-2Kk antigens on mouse spleen lymphocytes

We have studied the diffusion and aggregation of H-2Kk antigens labeled with a fluorescent anti-H-2Kk monoclonal antibody (IgG) on mouse splenic lymphocytes, employing fluorescence photobleaching recovery and fluorescence microscopy. The H-2Kk antigens were initially distributed homogeneously on all lymphocytes. Upon antibody binding, sub-micron patches were formed on 50-60% of the cells. A lateral diffusion coefficient, D, of 7.1 X 10(-10) cm2/s and a mobile fraction of 0.73 were found for H-2Kk antigens on diffusely-labeled cells, while these antigens were immobile (D less than or equal to 5 X 10(-12) cm2/s) on patched cells. The patched and nonpatched sub-populations did not correspond to B- and T-lymphocytes. Subjection to low temperature or treatment with NaN3 or cytoskeleton-disrupting drugs did not affect the diffusion or patching of H-2Kk, indicating no involvement of metabolic energy or drug-sensitive cytoskeletal components. These findings could be related to the interactions of H-2 antigens on the cell surface, and to the different susceptibilities of various cells to lysis by cytotoxic T-cells.     

H-2 histocompatibility antigens of subcellular membranes of mouse liver

Purified fractions of plasma membrane, Golgi apparatus, rough endoplasmic reticulum vesicles, nuclear envelope, and mitochondria were isolated from mouse liver and the distribution of H-2 histocompatibility antigens determined by indirect radioimmunoassay before and after membrane disruptive treatments. Fractions enriched in plasma membrane (surface membrane) revealed H-2 antigens in highest concentration; disruptive treatments were not necessary to reveal H-2 antigens with surface membranes. In contrast, internal membranes did not possess H-2 antigens which were accessible to antibody. Golgi apparatus fractions or some component of these fractions (e.g. secretory vesicles) possessed the antigens but in a latent form where accessibility was provided by simple rupture of the membrane vesicles. With endoplasmic reticulum, detergent solubilization of the membranes was required before H-2 antigen could be detected. Nuclear envelope preparations contained little or no demonstrable H-2 activity. These results were confirmed by several techniques including immunoprecipitation of labelled solubilized membrane components with anti-H-2 serum and subsequent analysis in SDS-PAGE.     

Purification and chemical characterization of papain-solubilized histocompatibility-2 antigens from mouse liver.

A large scale purification of histocompatibility-2 (H-2) antigens from mouse liver is described. The antigens were solubilized by a limited papain digestion of a crude preparation of liver membranes (strain A/J) and purified by ion exchange chromatography, gel filtration, affinity chromatography, and isoelectric focusing. The overall degree of purification of H-2Kk was 1,300-fold and that of H-2Dd was 1,500-fold; approximately 8 mg of purified H-2a antigens were obtained from 1 kg of liver. The purification was followed by a sensitive radioimmunoassay in which H-2a-containing fractions were used to inhibit the binding of 125I-labeled H-2a to appropriate antisera. H-2Dd and H-2Kk co-purified through all the steps but the concentration of H-2Kk was 2- to 3-fold higher than that of H-2Dd in the liver homogenate as well as in the purified H-2 preparation. beta 2-microglobulin was initially present in a 3- to 10-fold excess over H-2 in the liver homogenate, but the purified H-2 preparation contained approximately 2 mol of alloantigenic heavy chain/mol of beta 2-microglobulin. Isoelectric focusing and disc-gel electrophoresis showed a charge heterogeneity of H-2, with a mean isoelectric point of pH 4.9. Electrophoresis on sodium dodecyl sulfate gels showed one band. Denaturing conditions were required to remove beta 2-microglobulin and small amounts of impurities from H-2. The amino acid sequence of the first 27 residues of the isolated heavy chains was determined.     

Immunocytochemical localization of class I H-2 histocompatibility antigens of mouse liver

The subcellular location of class I H-2 histocompatibility antigens was determined for mouse liver using immunocytochemical techniques and correlated with information determined by cell fractionation and analysis in situ. Surface antigens first were localized by standard procedures involving surface labeling with ferritin-labeled antibody. This approach could not be used for internal membranes either in situ or in fractions since the antigens are not expressed at the cytoplasmic surface. For this purpose, thin sections of tissues embedded in Lowicryl were analyzed and quantitated. The in situ analysis confirmed the presence of H-2 antigens on internal membrane compartments as well as on the cell surface and helped rule out the possibility that distributions based on analyses by immunoprecipitation of fractions of internal membranes were influenced greatly by plasma membrane contamination. Quantitation was provided by immunoprecipitation of H-2 antigens from radioiodinated or metabolically labeled isolated and highly purified cell fractions. The findings establish the presence of class I H-2 histocompatibility antigens in endoplasmic reticulum, Golgi apparatus and plasma membrane in the approximate ratios of 1:3:7. No class I H-2 histocompatibility antigens could be detected in mitochondria, salt extracts of isolated membranes or NP-40-insoluble membrane material.     

Astrocytes produce interferon that enhances the expression of H-2 antigens on a subpopulation of brain cells

Using primary culture methods, we show that purified astrocytes from embryonic mouse or rat central nervous system (CNS) can be induced to produce interferon (IFN) activity when pretreated with a standard IFN-superinducing regimen of polyribonucleotide, cycloheximide, and actinomycin D, whereas IFN activity was not inducible in neuronal cultures derived from mouse CNS. Astrocyte IFN displays inductive, kinetic, physicochemical, and antigenic properties similar to those of IFN-alpha/beta, but is dissimilar to lymphocyte IFN (IFN-gamma). Treatment of pure astrocytic cultures or astrocytes cultured with neurons with astrocyte IFN or IFN-alpha/beta induced a dramatic increase in the expression of H-2 antigens on a subpopulation of astrocytes. Neither neurons nor oligodendroglia expressed detectable levels of H-2 antigens when exposed to astrocyte IFN, IFN-alpha/beta, or to IFN-beta. Injection of astrocyte IFN or IFN-alpha/beta directly into brains of newborn mice indicated that H-2 antigens were also induced in vivo. None of the IFNs (astrocyte, alpha/beta, or beta) tested induced Ia antigens on CNS cells in vitro or in vivo. Since H-2 antigens have a critical role in immune responses, astrocyte IFN may initiate and participate in immune reactions that contribute to immunoprotective and immunopathological responses in the CNS.     

Differential expression of alloantigens of the major histocompatibility complex on unfertilized and fertilized mouse eggs

Mouse oocytes at the dictyate and metaphase II stages as well as fertilized eggs have been studied by indirect immunofluorescence for the expression of H-2 histocompatibility antigens on surface membranes. Serologically specific reactivity to H-2 antibody was observed as patchy fluorescence distributed over the surface of the oocyte membrane. In contrast, one-cell zygotes exhibited variable reactivity, and early two-cell stages were negative. Absorption studies confirmed the serologic specificity of the reactivity on oocytes, which could be shown to be due to H-2 antibody. The results suggest that fertilization results in altered expression of major histocompatibility complex surface antigens, and confirms earlier studies that cleavage stage mouse embryos are not reactive with H-2 antibody.