Original H-2d and alien H-2k-like antigens of a BALB/c fibrosarcoma as defined by in vitro and in vivo studies of cell-mediated immunity

The present study examines the immunosensitivity and the immunogenicity of both original H-2^d and alien H-2^k-like antigens of the BALB/c (H-2^d) fibrosarcoma C-1 as detected by in vitro and in vivo cell-mediated cytotoxicity (CMC) assays. It was found that ⁵¹Cr-labeled C-1 cells were lysed in vitro by C 57 BL/6 anti-H-2^d lymphocytes. The specificity of this reaction was shown by cold inhibition experiments in which the anti-H-2^d cytotoxic activity on YC8 (H-2^d) targets was inhibited by unlabeled YC8 or C-1 but not by C3UR11 (H-2^k) tumor cells. Both D^d- and K^d-encoded antigens were recognized by appropriate cytotoxic effectors. The immunogenicity of H-2^d antigens of C-1 was revealed by the ability of C 57 BL/6 anti-C-1 lymphocytes to lyse YC8 targets. The expression of H-2^k-like alien alloantigens on C-1 was indicated by the finding that anti-H-2^k cytotoxic T lymphocytes (CTL), generated by culturing BALB/c spleen cells immune to BALB.K (H-2^k), C3Hf (H-2^k) or A (H-2^a = H-2^k/d) tissues with the cells of the same strain used for immunization, lysed C-1 targets. The cytotoxicity of these anti-H-2^k CTL against C 3 UR11 (H-2^k) targets could be specifically inhibited by cold C 3 UR 11 or C-1 cells but not by two other BALB/c tumors. Using recombinant H-2-congenic mice, it was shown that both D^k and K^k antigens were recognized by CTL on C-1 cells. The immunogenicity of the H-2^k-like antigens, however, could not be detected in vitro. In fact, effector spleen cells from BALB/c mice immune to C-1 did not develop any detectable cytotoxicity against C 3 UR 11 targets as assayed either by a direct in vitro test or after in vitro restimulation with C-1 sarcoma cells. A similar experimental design was adopted in Winn assays carried out by mixing spleen cells of BALB/c immune mice with either C-1 or C3 UR 11 targets and injecting the mixtures in BALB/c or hybrid recipients. These in vivo tests revealed the presence of both H-2^d (K^d and D^d) and H-2^k-like (K^k and D^k) antigens on C-1. At variance with the in vitro CMC assays, however, the Winn assay also detected the immunogenicity of the H-2^k alien antigens, since BALB/c anti-C-1 spleen cells were able to significantly reduce the growth of C 3 UR 11 lymphoma cells in (BALB/c × C 3 Hf)F₁ hosts.     

EXPRESSION OF FOREIGN H-2-LIKE ANTIGENS BY A CHEMICALLY-INDUCED MURINE TUMOUR (MCG4)

Alien H-2^k-like antigens were found to be expressed by a methylcholanthrene induced tumour of BALB/c (H-2^d) origin. H-2 specificities of the k haplotype were detected on this tumour by a variety of serological techiques, including ⁵¹Cr-release cytotoxicity, microradioassay and absorption. The antisera employed were conventional polyspecific alloantisera, typing sera with restricted specificty and monoclonal hybridoma-derived anti-H-2^k antibodies. The tumour has a low expression of the private specificty 31, which characterizes K^d molecules, and does not seem to express the private specificities of D^d, K^k and D^k molecules. It appears to express predominantly alien H-2-like antigens which are very similar to but not identical with normal H-2^k molecules.     

MULTIPLE FOREIGN NON-H-2 DETERMINANTS ON THE SURFACE OF A CHEMICALLY-INDUCED MURINE SARCOMA*

By immunizing BALB/c (H-2^d mice against normal tissues from C57BL/6J (H-2^b), C3Hf (H-2^k) and DBA/2 (H-2^d), but not from AKR (H-2^k) strains, resistance was induced to the subsequent challenge of the ‘syngeneic’ methyl-cholanthrene-induced BALB/c sarcoma ST5; lymph node cells from allo-immune BALB/c mice were also able to exert a parallel cytotoxic effect against in vitro cultured ST5 cells. The involvement of foreign H-2 specificities in the observed cross-reactions was ruled out by absorptions of H-2 monospecific sera and by the interallelic combinations used, thus suggesting that non-H-2 histocompatibility antigens were responsible for the above findings. By using the indirect isotopic antiglobulin assay, BALB/c anti-C57BL/6J and anti-C3Hf polyspecific sera were found to bind specifically to cultured ST5 cells. C57BL/6J and C3Hf, but not DBA/2, lymph node cells were able to absorb the anti-ST5 activity of the anti-C57BL/6J serum. These results indicated that ST5 cells expressed on their surface at least two different sets of foreign non-H-2 antigens: one shared by C57BL/6J and C3Hf tissues, and detected by both cell-mediated and serological techniques; the other one belonging to DBA/2 tissues, and revealed mainly at the cell-mediated level.     

The presence of a common idiotype in anti-H-2 immune sera as detected by anti-idiotype to a monoclonal anti-H-2 antibody

To study the idiotypes (Id) of the humoral response to H-2L^d antigens, xenogeneic antisera were produced to three independent monoclonal antibodies, recognizing L^d determinants H-2.64 or 65. The reactivity of each of these anti-Id was specific for the immunizing antibody, no cross-reactions among the three anti-L hybridomas being detectable. Antisera produced in BALB/c H-2^dm2 mice hyperimmunized with BALB/c tissue were examined for the presence of cross-reactive Id (Id^CR). When the ability of these anti-Id to inhibit the binding of alloantibodies to L^d splenic antigens was tested, a broadly shared Id was detected by one anti-Id (anti-23-10-1S). The shared Id represented between one-fourth and one-half of the total anti-L^d humoral response and was found in every BALB/c H-2^dm2 anti-BALB/c serum tested. The Id^CR was limited to those alloantibodies reacting with the determinant H-2.65 which corresponds with the serologic reactivity of monoclonal antibody 23-10-1S. The other two anti-Id did not detect components of the anti-L^d humoral response, even though one of these was made against monoclonal antibody 30-5-7S which also detects serologic specificity H-2.65. The detection of a Id^CR in anti-L^d responses stands in contrast to our previous failure to detect Id^CR in anti-H-2K^k responses. Among the possible reasons for this contrast are (a) the fact that 23-10-1S is an IgM antibody, whereas the anti-H-2K^k antibodies studies were IgG; (b) the chance occurrence of anti-H-2 hybridomas with dominant Id and (c) the possibility that the anti-L^d antibody repertoire may be less heterogeneous than that directed to K^k antigens.     

H-2K RESTRICTION OF THE T CELL-MEDIATED LYSIS OF A CHEMICALLY-INDUCED BALB/c FIBROSARCOMA

Previous work has shown that a cytotoxic T lymphocyte (CTL) immune response of syngeneic mice immunized with a chemically-induced BALB/c (H-2^d) fibrosarcoma was directed against an individual tumour-associated antigen. To see whether this reaction was restricted by products of the major histocompatibility complex (MHC), anti-H-2 alloantisera to K or D antigens were used to interfere with the CTL-mediated immune response. Antisera to K^d but not to D^d antigens inhibited the lytic activity of CTL against fibrosarcoma cells. In addition, the study of the CTL response in F₁→ P antitumour immunized chimeric mice showed that antitumour cytotoxicity developed only when F₁ and parental host shared the K^d region. Both experiments strongly indicate that recognition of the individual tumour-associated antigen of the BALB/c fibrosarcoma is restricted by the products of H-2K^d genes.     

Cell-mediated anti-tumor response in the RLmale 1 system. I. T nature, H-2Dd involvement and antigenic specificity of the effector cells.

After in vivo priming and in vitro secondary stimulation by the radio-induced RL♂ 1 lymphoma cells, syngeneic BALB/c splenic lymphocytes evidenced a specific but very weak cytolytic activity against RL♂ 1 target cells. Under the same experimental conditions, spleen cells from (B6 x BALB/c)F₁ were at least 100 times more efficient. In both cases, the effector cells were cytolytic T lymphocytes (CTL). Normal H-2D^d antigens of the tumor cell surface were involved in the effector-to-target cell interaction since anti-H-2 or anti-H-2D^d antisera abolished the RL♂ 1 cytolysis by immune syngeneic CTL, whereas anti-H-2K^d were devoid of blocking activity. The testing of a series of lymphoma cells, either virus-induced or not, belonging to different H-2 haplotypes, show that the immune CTL were highly specific for RL♂ 1 target cells. Only with the P815 mastocytoma cells was a weak cross-reactivity detected by both direct tests and competition experiments. Allogeneic (H-2^k) AKR lymphoma cells which share the X1 antigen with RL♂ 1 do not react, possibly due to an H-2 restriction of the CTL activity. The CTL-reacting antigen cannot be definitely identified, since several specificities, including the serologically defined X1 antigen, are possibly involved simultaneously. The Hh antigens which could have accounted for the F₁ anti-parent reaction, appear irrelevant.     

EQUIVALENT DECREASE OF H-2Kk AND H-2Dk EXPRESSION AFTER VACCINIA VIRUS INFECTION

Expression of H-2K^k and H-2D^k molecules was studied by indirect immunofluorescence on vaccinia virus-infected L_s cells (derived from the L929 cell line), using D-23^b and ASA-21 monospecific alloantisera, respectively directed against the H-2.23 and H-2.32 private specificities of the H-2^k haplotype. Our study demonstrates that the increase in vaccinia virus-induced antigens on the membrane of infected cells (as a function of the multiplicity of infection) is associated with a concomitant decrease in the expression of both H-2K^k and H-2D^k serologically defined private specificities. Absorption experiments of D-23^b and ASA-21 sera, using infected or uninfected L_s cells, also indicate that after virus infection, H-2K^k and H-2D^k private specificities are equally altered in their serological expression. We finally show that this alteration consists in a mere quantitative decrease of H-2 molecules, since the cytolytic capacity of a rabbit anti-H-2 serum, specifically reacting against the constant part of the heavy chains of H-2 molecules, was significantly more absorbed by uninfected cells than by infected cells. We conclude that no preferential decrease in the expression of H-2 K^k and H-2 D^k molecules is induced during cell infection by vaccinia virus.     

IMMUNOLOGICAL CROSS-REACTIVITY BETWEEN H-2DK PRODUCT AND DTIC - TREATED H - 2d LYMPHOMA

The experiments reported here concern the charcterization by techniques of in vitro cell-mediated immunity of the antigens induced by 5-(3,3'dimethyl-1-triazine)-imidazole-4-carboxamide (DTIC) on L1210, a chemically-induced lymphoma of DBA/2 mice (H-2^d). This series of experiments with the DTIC-treated L1210 tumour show the presence of an H-2D'-like antigen which resembles the D^k gene product/s of the H-2^k haplotype.     

Lack of H-2Ld locus products on a BALB/c fibrosarcoma expressing H-2k-like alien antigens

The presence of H-2Ld antigens was evaluated in methylcholanthrene-induced BALB/c fibrosarcomas by a variety of approaches. Transplantation experiments showed that BALB/c-H-2dm2 mice, a mutant strain whose cells do not express H-2Ld antigens, after immunization with BALB/c normal tissues developed a resistance to the growth of two tumours (C-3 and GI-17), but not to a third neoplasm, C-1, which is known to have H-2d- as well as H-2k-like alien antigens. In vitro experiments with cytotoxic T lymphocytes generated against Ld antigens confirmed a loss of Ld antigens on C-1 but not on C-3 tumour cells. Serological experiments with an anti-Ld serum again revealed the presence of H-2Ld determinants on C-3 but not on C-1 cells. Biochemical analysis in SDS-PAGE of immunoprecipitates obtained by specific anti-H-2 sera with NP40 lysates of the tumours studied could detect H-2Kd, H-2Dd and H-2Ld antigens in C-3 fibrosarcoma cells whereas Kd and Dd were the only H-2d molecules found in C-1 lysate along with the H-2k-like specificities. The possible genetic mechanisms which may explain this apparent gain and loss modification of the H-2 profile of C-1 are discussed.     

COINCIDENT EFFECT IN THE GRAFT-VERSUS-HOST REACTION OF BALB/c LYMPHOID CELLS DERIVED FROM MICE IMMUNE EITHER TO ALLOGENEIC NORMAL TISSUE OR TO SYNGENEIC CHEMICALLYINDUCED FIBROSARCOMATA

By using the graft-versus-host reaction (GVHR) based on the spleen enlargement test of Simonsen (1962), lymphocytes from BALB/c mice immune to syngeneic ST2 or ST5 sarcomata were shown to behave like BALB/c anti-DBA/2 lymphocytes in specifically increasing the GVHR in (BALB/c × DBA/2)F₁ newborns as compared with non-immune BALB/c cells. No such effect was evident when BALB/c anti-ST2 or anti-ST5 lymphoid cells were given to (BALB/c × C3Hf)F₁ and to (BALB/c × AKR)F₁ mice; anti-ST5 lymphocytes were also ineffective into (BALB/c × C57BL/6)F₁ newborns in which anti-ST2 lymphocytes were able to increase the GVHR over the background induced by non-immune BALB/c cells. A third immunogenic BALB/c fibrosarcoma C-1 was able to activate syngeneic lymphocytes which gave an augmented GVHR in (BALB/c × C3Hf)F₁ and (BALB/c × AKR)F₁ but not in the other hybrids. The efficacy of BALB/c anti-ST2 or -ST5 lymphocytes in reproducing a BALB/c anti-DBA/2 like anamnestic response in (BALB/c × DBA/2)F₁ mice support previous findings indicating that non-H-2 alien histocompatibility antigens of the DBA/2 strain, are expressed on these tumour cells. The GVHR induced by lymphoid cells immune to C-1 tumour are also in keeping with serological and transplantation studies (reported elsewhere) indicating the expression of foreign H-2^k antigens on this sarcoma.     

SEROLOGICAL AND IMMUNOCHEMICAL STUDIES OF H-2 ALLOSPECIFICITIES ON k36, A SYNGENEIC TUMOUR OF AKR

Expression of H-2 antigenic specificities on K36, a spontaneous leukaemia originating from AKR (H-2^k) mice, was studied by serology and immunochemistry. Two ascites lines of the tumour, as well as a tissue culture adjusted and cloned tumour line, were used in these studies with similar results being obtained. K36 expresses on its cell surface D-region encoded H-2K antigens but does not express K-region encoded H-2K alloantigens. It also expresses on its cell membrane, H-2 specificities of foreign haplotypes not present on normal AKR lymphoid cells. The molecular basis of the H-2D^d specificity on K36 (H-2^k was analysed by immunoprecipitation and polyacrylamide gel electrophoresis. The specificity was shown to be present on a glycoprotein of apparent molecular weight 45,000. However, antisera against the H-2D^d private specificity (H-2.4) precipitate additional glycoprotein of 45,000D and also 70,000D. In tryptic peptide maps of the isolated 45,000D fraction precipitated by anti-H-2.4 serum from radiolabelled K36 glycoprotein, all H-2D^d specific peptides were present in the same quantitative ratio. This is consistent with the structural identity of the foreign H-2D^d from the K36 tumour with normal H-2D^d and supports the hypothesis of a regulator system controlling the H-2 allelism. Under certain circumstances such a system could cause suppression of one and derepression of the other H-2 gene products.     

H-2d-LIKE SPECIFICITIES ON GARDNER (H-2k) TUMOUR DETECTED IN A RESTRICTED ANTI-TUMOUR REACTION

Cytostatis of the H-2^d tumour LSTRA by H-2-restricted effector lymphocytes was inhibited by antisera against H-2.4 and H-2.31 but not by antisera against public specificities or non-H-2 antigens. The unexpected reaction of the same effector cells against Gardner tumour (H-2^k) was also shown to be inhibited by a combination of antisera against H-2.4 and H-2.31 but not by each antiserum used separately. The inhibitory capacity of these antisera was removed by absorption with B10.D2 but not with B10 lymphocytes. This indicated the presence of H-2^d-like specificities on gardner tumour which could function as self-recognition structures in an H-2K^d and H-2D^d restricted system.     

IMPAIRED H-2 EXPRESSION IN B 16 MELANOMA VARIANTS

We studied the expression of H-2^b alloantigens in three different B16 melanoma lines cultured in vitro, Cell lines were B16-F1 and two cell cultures (named B16-A and B16-B) newly derived from two different in vivo sublines of B16 melanoma. The assays used were in vivo tumour growth in allogeneic (BALB/c and B10.BR) as compared to syngeneic mice, in vitro cell-mediated cytotoxicity by anti-H-2^b immune lymphocytes and absorption of anti-H-2^b antisera activity. The B16-F1 line was able to efficiently kill allogeneic hosts, could not be lysed by anti-H-2^b cytotoxic effectors and did not express any serologically detectable amount of H-2^b alloantigens. The B16-A line was H-2 positive during the early in vitro passages, then, at the 8th–10th passages, it acquired the capacity to kill allogeneic hosts, lost the sensitivity to anti-H-2^b cytotoxic effectors and the H-2K^b antigens became undetectable. The expression of H-2D^b was reduced, although at a lower degree. Similar data were obtained with B 16-B cells, which after 10 in vitro passages grew and killed allogeneic hosts, showed a decreased sensitivity to cytotoxic anti-H-2^b effectors and a very low expression of the K region antigens. The results indicate that H-2 expression is altered in B 16 melanoma lines and this may influence the different metastatic capacity of such cells.     

MEMBRANE ANTIGENS RECOGNIZED BY HETEROANTISERA AGAINST MOUSE TUMOURS,TESTED IN CELL LINES OF DIFFERENT H - 2 HAPLOTYPES

The pattern of reactivity of two heteroantisera against mouse tumour cells (rabbit anti-Meth A sarcoma: RAMA; and rabbit anti-RBL-5 leukaemia: RAR-5) has been studied in various cell lines of different H-2 haplotypes in complement-dependent cytotoxicity tests using a microadioassay. RAMA was cytotoxic not only for Meth A (H-2^d) but also for MCG4, P815Y, LSTRA, YC8 (H-2^d), L929, TLC5, Gardner (H-2^k), RBL-5 and TLX/9 (H-2^b). RAR-5 similarly killed RBL-5, as expected, as well as Meth A, P815Y, MCG4, SL2, YC8, LSTRA (H-2^d), L929 (H-2^k), TLX/9, MBL2, Gil IV, EL4 (H-2^b) and YAC (H-2^a). The cross-cytotoxicity RAMA-RBL-5 and RAR-5-Meth A was abolished when RAMA or RAR-5 were absorbed with allogeneic tissues from C57B1/6, BALB/c, CBA/H, C57B1/10 (B10), B10.BR, B10.D2, but not with rat lymphoid cells. A species-specific antigen present in these strains of mice thus appeared to be responsible for this cytotoxicity. The direct killing obtained with RAMA on Meth A and RAR-5 on RBL-5 was not absorbed by: (a) allogeneic cells of C57B1/6, CBA/H, AKR, B10, B10.BR, B10.D2 for RAMA, and CBA/H, BALB/c, B10, B10.BR, B10.D2 for RAR-5; or (b) syngeneic normal lymphoid cells (BALB/c and C57B1/6 respectively). This suggests the presence of a heteroantibody in the sera recognizing structures at the tumour cell surface that are absent in normal lymphoid cells—a tumour-specific antigen (TSA). Finally, the TSA of Meth A (recognized by BALB/c-absorbed RAMA) did not cross-react with eight mouse cell lines of different aetiology and origin: MCG4, P815Y, Gardner, TLC5, L929, TLX/9, LSTRA and RBL-5. However, the TSA of RBL-5 (recognized by C57B1/6 absorbed RAR-5) reacted not only with RBL-5 but also with tumour cells induced by viruses antigenically related to Rauscher, belonging to the group FMR Gi. It reacted also with EL4, a tumour cell line not virus induced, and weakly with SL2, a spontaneous tumour cell line. It did not react with TLX/9 (X-ray induced) or Meth A (chemically induced). From these results it is concluded that heteroantisera against mouse tumour cells recognize at least species-specific antigens and tumour-specific antigens.     

VARIABLE EXPRESSION AND IMMUNOGENICITY OF AN H-2K-CODED ALLOANTIGEN ON MURINE TUMOURS

The K region of the H-2 major histocompatibility complex (MHC) of mice of H-2K^k haplotype codes for two distinct alloantigens. One of these alloantigens, designated k-common, is expressed by C3HfB/HeN mice (C3Hf). The other alloantigen, designated k-unique, is not expressed by C3Hf mice. The H-2 haplotype of C3Hf mice has been classified as kv1 and the variant antigen distinguishing this strain from mice of H-2K^k haplotype has been designated kv1-unique. Several transplacentally-induced lung tumours of C3Hf mice express the k-unique, rather than the expected kv1-unique, antigen. The immunogenicity of the k-unique antigen on C3Hf-derived lung tumours varies with different tumours. In particular, the capacity of the k-unique antigen to induce radioresistant immunity in C3Hf mice appears to be lost on long term cultured tumour cells even though the tumour remains susceptible to in vivo immune responses directed against the k-unique antigen. Alterations in expression and in immunogenicity of unique H-2-coded antigens may dictate the nature and efficacy of immune surveillance of autochthanous tumours.     

UNEXPECTED LYMPHO-CYTOTOXIC REACTIONS OF ANTI-H-2 SERA ON NORMAL LYMPH-NODE CELLS: ARE THEY DUE TO ALTERED H-2 STRUCTURES OR ANTI-VIRAL ANTIBODIES?

When testing the serum of an individual anti-H-2 immunized mouse (B10 x A.SW)F₁ anti-B10.M by the routine micro-lymphocytotoxicity test on lymph-node cells, unexpected antibodies were found. The most striking finding was that after absorption of anti-H-2.8 antibodies with B10.A(2R) (K^k) cells, antibodies remained which reacted with AKR, B10.AKM and B10.A V + mice while B10.A V-, B10.BR and C3H mice were negative. While all these strains share the K^k allele, only the positively reacting strains express high titres of infectious RNA turnover viruses. Unexpected reactions were observed also with H-2^d, H-2^j and H-2^r cells and absorption experiments indicated two or three antibody populations. These reactions could be interpreted by two different possibilities: (1) anti-H-2 antibodies react with virus-altered H-2 structures; and (2) antiviral antibodies react with H-2 structures complexed with viruses. These possibilities should be taken into account when H-2 sera are tested on tumour or virus-infected cells.     

Association Between H-2 Antigens and Thyroglobulin Influences the Immunogenicity of Thyroglobulin in Mice

To ascertain the role of H-2 in the immunogenicity of thyroglobulin, congenic strains of mice, B10.BR (H-2^khigh-responder) and B10.02 (H-2^d, low-responder) were immunized with purified thyroglobulin (from B10.BR and B10.D2) which was or was not passed through affinity columns of Sepharose coupled to anti-H-2^k or anti-H-2^d sera. Thyroglobulin absorbed with the same anti-H-2 as its source did not induce thyroglobulin antibodies or thyroid infiltrates in mice of the same strain and induced thyroid lesions but no antibodies in mice of the opposite strain. These experiments suggest that thyroglobulin, an autoantigen, is associated with syngeneic histocompatibility antigens in vivo and this association is important for the (auto) antigenicity of thyroglobulin.     

Immunogenicity of H-2 positive and H-2 negative clones of a mouse tumour, GR9

The GR9 tumour was induced with methylcholanthrene in a BALB/c mouse, adapted to tissue culture and cloned without any passage in vivo GR9 clones were typed for H-2 with three monoclonal antibodies that define H-2Kd + Dd, Kd and Dd antigens. A great heterogeneity of H-2d expression was found from clones which were Kd and Dd positive to clones Kd and Dd negative. These results were confirmed for A7 and B9 clones using immunoprecipitation with anti-H-2D.4 and anti-H-2K.31 alloantisera and SDS-PAGE analysis. In addition, the number of chromosomes per cell was heterogeneous amongst the clones, ranging from 38 +/- 2 to pseudotetraploid clones which have 75 +/- 2 chromosomes. GR9 clones were injected into syngeneic BALB/c mice to measure local tumour growth. We found that the growth correlated with the amount of H-2 antigen expressed, i.e. clones with low H-2d expression were highly malignant while clones with normal H-2d expression were highly immunogenic. Finally we found that BALB/c mice immunized against A7 (Kd, Dd-positive) protected against A7, as expected, but surprisingly also against B9 (Kd, Dd-negative).     

ABSENCE OF FOUR H-2d ANTIGENIC SPECIFICITIES IN AN H-2d SARCOMA

MCG4 is a BALB/c sarcoma induced as a solid tumour with 0.2 mgs of methylcholantrene. The primary tumour was serially transplanted subcutaneously in syngeneic mice. The ascites form obtained was used to study the expression of H-2 antigeneic specificities in a postlabelling radioassay. MCG4 did not express H-2D.4 (private specificity of H-2^d haplotypes) as well as H-2.3, H-2.8 and H-2.13 (public specificities). In addition it expressed H-2.5 (a public specificity not present in H-2^d cells). These results were confirmed by quantitative absorption analysis using MCG4 and positive-negative normal lymphoid cells for a particular specificity. Results are discussed with regard to the control of expression of H-2 antigens by regulatory genes.     

Major histocompatibility complex regulation of interleukin-5 production in the mouse

Lymph node cells of CBA (H-2^k), but not of BALB/c (H-2^d) mice immunized epicutaneously with picryl chloryde secrete interleukin (IL)-5 when stimulated with the specific antigen in vitro. The low IL-5 production in BALB/c mice persists when either picryl chloride or the unrelated antigen oxazolone are used, when the amount of antigen in vitro is varied and when a secondary response is studied. The difference in IL-5 production maps to the major histocompatibility complex (MHC) in the congenic BALB/b, BALB/c and BALB/k mice. Furthermore, lymph node cells from (k × d) F₁ mice produce IL-5 when stimulated by antigen presented on H-2^k but not on H-2^d antigen-presenting cells. Finally, the low IL-5 production in vitro in BALB/c mice is correlated with low picryl-specific IgA levels in vivo, which otherwise are ten times greater in CBA and BALB/k mice. The influence of MHC on IL-5 production and IgA secretion in the mouse might be a possible basis for the association of MHC with IgA deficiency in humans.