Effect of anH-2 mutation on cytotoxic T cell recognition. Specific antigen can determine the pattern ofH-2 restriction

Hz1 (H-2 ^bm1 ) mice, an H-2 mutant strain derived from C57BL/6(H-2 ^b ), were either injected with vaccinia virus or had their spleen cells sensitized in vitro with syngeneic TNP-modified cells. The cytotoxic cells generated were tested for their activity against target cells that were either infected with vaccinia virus, TNP-modified, or both vaccinia infected and TNP-modified.Hz1 anti-TNP cytotoxic cells specifically lysed syngeneic target cells that were trinitrophenylated but not infected with vaccinia virus, while anti-vaccinia cells specifically lysed vaccinia infected target cells but not TNP-cells. Hz1 (H-2K ^bm1 D ^b ) anti-TNP effector cells killed B10.A(5R)-TNP (H-2K ^b D ^d ) targets, indicating that there is cross-reactivity between TNP-H-2K^b and TNP-H-2K^bm1. On the other hand, there is no cross-reactivity between vaccinia-H-2K^b and H-2K^bm1, since Hz1 anti-vaccinia effector cells did not kill vaccinia infected B10.A(5R) targets.Since Hz1 anti-TNP effector cells lysed B10.A(5R) target cells that were first infected with vaccinia virus and then derivatized with TNP, virus does not mask cross-reactive determinants shared by TNP-H-2K^b and H-2K^bm1. Additional experiments showed that Hz1 anti-TNP effector cells lysed TNP-modified and vaccinia infected B10.A(5R) target cells irrespective of the virus concentration used for infection or the time of addition of virus. Further, there are no detectable quantitative differences between C57BL/6 and Hz1 anti-TNP effector cells in their ability to kill TNP-5R targets.The cytotoxic effect of Hz1 anti-TNP effector cells on B10.A(5R)-TNP targets could not be blocked with TNP derivatized inhibitor cells that carry theH-2D ^d region allele. Thus, the ability of anti-TNP H-2K^b effector cells to cross-react with H-2K^bm1 cannot be explained by a cross-reaction between H-2K^bm1 and H-2D^d.Abbreviations used in this paper TNP trinitrophenol - PFU plaque forming unit - Con A Concanavalin A - BSS balanced-salt-solution - FCS fetal calf serum - TNBS trinitrobenzene sulfonic acid - PBS phosphate-buffered-saline     

Immunogenetic analysis ofH-2 mutations

A.BY, B10.LPa, and B10.129(5M) mice were presensitized in vivo against B10.A(5R) cells and then restimulated in vitro by the same cells in the standard CML assay. The effector cells thus generated lysed not only B10.A(5R), but also C57BL/6 targets, indicating that, in addition to anti-H-2D_d response [measured on the B10.A(5R) targets], response to minor histocompatibility (H) antigens (measured on the C57BL/6 targets) also occurred. The latter response was directed against multiple minor H antigens in the case of the A.BY effectors, and against H-1 and H-3 antigens in the case of B10.129(5M) and B10.LPa effectors, respectively. The sensitization against minor H antigens occurred in the context of H-2K^b H-2D^d antigens, but by testing the response on C57BL/6 targets, only cells reacting with minor H antigens in the context of H-2K^b were assayed. The same effector cells were then tested against H-2^b mutant strains, in which theH-2K ^b allele was replaced by a mutant one. All three effector types [A.BY, B10.LPa, and B10.129(5M)] behaved in a similar way: they all reacted with theH-2 ^bg1 mutant to the same degree as withH-2 ^b, they did not react at all or reacted only weakly with theH-2 ^bd andH-2 ^bh mutants, and they reacted moderately or strongly with theH-2 ^ba mutant. The degree of crossreactivity with the mutants reflects, with one exception, the degree of relatedness of these mutants toH-2 ^b, as established by other methods. The one exception is theH-2 ^ba mutant, which is the most unrelated toH-2 ^b, and yet it crossreacted strongly. Further testing, however, suggested that in this instance the crossreactivity was probably directed against H-2 antigens: the anti-H-2D^d effectors apparently crossreacted with the H-2K^ba antigens. This finding is an example of cell-mediated crossreactivity between the products of two differentH-2 genes (H-2K andH-2D). It is also an example of anH-2 mutation generating an antigenic determinant known to be present in another strain.     

Spleen cells from animals neonatally tolerant to H-2Kk antigens recognize trinitrophenyl-modified H-2Kk spleen cells

A.TL mice injected with (A.AL × A.TL)F₁ cells within 24 hours after birth were rendered tolerant to H-2K^k antigens, as evidenced by acceptance of A.TL skin grafts. When spleen cells from these tolerant animals were cocultured with A.AL stimulator cells, no cytotoxic effector cells were generated in a cell-mediated lympholysis assay. However, when the A.AL stimulator cells were derivatized with trinitrophenol, effector cells that displayed a cytotoxic effect against trinitrophenyl-modified H-2K^k target cells were generated. These data indicate that animals tolerant to H-2 determinants but chimeric to only a minor extent possess cytotoxic precursor cells in sufficient frequency to mount a primary in vitro response against trinitrophenol in the context of an allogeneicH-2K region.     

H-2 effects on cell-cell interactions in the response to single non-H-2 alloantigens

Immune response (Ir) genes mapping in theI region of the mouseH-2 complex appear to regulate specifically the presentation of a number of antigens by macrophages to proliferating T cells. We have investigated the possibility that similarIr genes mapping in theH-2K andH-2D regions specifically regulate the presentation of target antigens to cytotoxic effector T cells. We report that the susceptibility of targets expressing specific non-H-2 H alloantigens to lysis by H-2-compatible, H-antigen-specific cytotoxic effector T cells is controlled by polymorphicH-2K/D genes. This control of susceptibility to lysis is accomplished through what we have defined operationally as antigen-specific regulation of non-H-2 H antigen immunogenicity. High immunogenicity of the H-4.2 alloantigen is determined by a gene mapping in theH-2K region ofH-2 ^b . However, high immunogenicity of H-7.1 is determined by a gene mapping in theH-2D region ofH-2 ^b . High immunogenicity of the H-3.1 alloantigen is determined by genes mapping in both theH-2K andH-2D regions ofH-2 ^b . Therefore, genes mapping in theH-2K andH-2D regions serve a function in presenting antigen to cytotoxic effector T cells. This function is analogous to that played byI-regionIr genes expressed in macrophages which present antigen to proliferating T cells. We present arguments for classification of theseH-2K/D genes as a second system ofIr genes and discuss the implications of twoH-2-linkedIr-gene systems, their possible functions, and their evolution.     

Identification of a new CML target antigen controlled by a gene associated with theQa-2 locus

BALB/cBy anti-BALB/cJ spleen cells were tested in a secondary cellmediated lympholysis assay. The effector cells generated displayed a positive cytotoxic effect against Con A lymphoblasts from only those strains that were typed serologically as having theQa-2 ^a allele. Confirmation that the target antigen is controlled by a locus closely associated with or identical toQa-2 was obtained by the findings that target cells from B6.K2 (Qa-2 ^a,Qa-3 ^a) mice were lysed by the effector cells, while those from theQa-2, 3 congenic strain B6.K1 (Qa-2 ^b,Qa-3 ^b) were not. The fact that target cells from aQa-2-positive/Qa-3-negative strain (DBA/1,Qa-2 ^ai,Qa-3 ^b) were killed indicates that the target antigen is controlled, at least in part, by theQa-2 locus, not the Qa-3.There is no observedH-2 genetic restriction for this cytotoxic effect, since target cells which have theQa-2 ^a allele but differ from the stimulator cells at theH-2K, D, andI regions were lysed efficiently.     

Cytotoxic T-cell responses to H-Y:Ir genes and associative antigens map inH-2

The secondary cytotoxic responses to the male-specific antigen (H-Y) in mice showH-2 restriction so that the cytotoxic female cell must share the K- and/or D-end antigen with the male target cells. The association with the K and/or D end varies with differentH-2 haplotypes,e.g., H-2 ^b cytotoxic cells require the H-2D^b antigen(s) on the target cells, while cytotoxic cells fromH-2 ^b/H-2 ^d F₁ mice sensitized toH-2 ^d male cells kill only male targets having H-2K^d antigen(s). This association of H-Y with appropriate K/D antigens seems to be needed also in the induction of the cytotoxic response. Of the independent haplotypes, onlyH-2 ^b strains are capable of making secondary anti-H-Y responses and this trait seems to be dominant,i.e., the F₁ strains with oneH-2 ^b parent are able to produce anti-H-Y cytotoxic cells against both theH-2 ^b parent and the nonresponder parent. The mating of the two nonresponder strains may produce F₁ mice which are responders, thus suggestingIr gene complementation. Mapping data indicates that at least one of these complementary genes is located in theI-C region fork/s complementation.     

Do histocompatibility antigens recognize themselves?

In the Simonsen spleen weight assay, theH-2K ^ba mutant does not respond against theH-2K ^bd mutant orH-2K ^bd /H-2K ^b hybrid, while the parentalH-2K ^b haplotype does respond. TheH-2K ^ba /H-2K ^b hybrid reacts strongly to bothH-2K ^bd andH-2K ^bd /H-2K ^b , indicating that the donor genotype could influence the reactivity against the same antigenic difference. The response of theH-2 ^ba mutant against a number of unrelated H-2 antigens does not differ from that of the parental haplotype. TheH-2K ^bd mutant reacts againstH-2K ^b andH-2K ^ba , and theH-2K ^b parent reacts against both theH-2K ^ba andH-2K ^bd mutants. The specific defect of reactivity in theH-2K ^ba mutant is effectively complemented by crossing with a number of unrelatedH-2 haplotypes. TheH-2 ^ka andH-2 ^fa mutants complement poorly compared to corresponding parental strains CBA and A.CA, while the B10.M (H-2 ^f ) strain does not complement at all (which is probably attributable to an undetectedH-2 mutation in the last strain). The data strongly suggest that the product of theH-2K locus-which is known to function as a transplantation antigen, lymphocyte activating determinant, and serologically defined antigen-also influences the immune response capacity against a mutant histocompatibility determinant.     

H-2-associated specificity of virus-immune cytotoxic T cells fromH-2 mutant and wild-type mice: M523 (H-2K ka ) and M505(H-2K bd ) do,M504 (H-2D da ) and M506(H-2K fa ) do not crossreact with wild-typeH-2K orH-2D

B10.A(3R) (H-2K ^b ) mice infected with lymphocytic choriomeningitis virus (LCMV) or vaccinia virus generate cytotoxic T cells capable of specifically lysing virus-infected macrophage target cells fromH-2K ^b mutant mice M505 (H-2K ^bd ), and vice versa. Similarly, virus-immune B10.A(4R) (H-2K ^k ) T cells specifically lyse infected targets from M523 (H-2K ^ka ), and vice versa. In contrast, virus-specific cytotoxic T cells from neither M504 (H-2D ^da ) and B10.A(5R) (H-2D ^d ) nor M506 (H-2K ^fa ) and B10.M(11R) (H-2K ^f ) mutually crossreact at the cytotoxic effector-cell level. As far as tested, the crossreactivity patterns between wild-type and mutantK orD specificities are identical for LCMV- and vaccinia virus-immune spleen cells. Although this finding is no proof for either the altered self nor the dual recognition concept of T-cell recognition, it may be compatible with the latter model.     

H-2 antigen variants in a cultured mouse leukemia cell line

We have investigated the effect of immune selection against a single gene product on a cultured mouse Friend leukemia cell line. The clonal cell line used is heterozygous at theH-2 complex and expresses theH-2 ^d andH-2 ^b haplotypes. The genes selected against were theH-2K locus alleles. Variants were obtained after a single-step selection using either antiH-2K^b or anti-H-2K^d serum. The phenotypes of the variants obtained showed an interesting asymmetry between the two haplotypes. Selection against theH 2K ^b allele resulted in the isolation of the two expected types of variant-those that had lost only H-2K^b and those that had lost both H-2K^b and the linked H-2D^b. Selection against H-2K^d yielded, exclusively, variants that had lost both the selected antigen and the linked H-2D^d. None of the variants showed an alteration in expression of antigens intrans configuration. Karyotypic analyses of the variants revealed that all the cells had retained both copies of chromosome 17 present in the wild-type cells. The results suggest that the variants did not emerge through chromosome loss.     

Detection of shared H-2Kk and H-2Dk antigens that function as self determinants for cell-mediated lympholysis to trinitrophenyl-self

Spleen cells from C3H/He mice immunized in vivo to trinitrophenyl (TNP)-self were sensitized in vitro to TNP-self. These spleen cells displayed strong lysis on TNP-modified H-2D end-matched (Kd-Dk) targets as well as enhanced cytotoxicity against H-2 matched (Kk-Dk) or H-2K end-matched (Kk-Dd) target cells. Cold target-blocking studies showed that the lysis of TNP-Kd-Dk targets could be blocked by the addition of TNP-modified Kk-Dk, Kk-Dd Kk-Db, or Kd-Dk, but not by TNP-modified Kd-Dd, Kb-Db and Kq-Kq spleen cells. These results demonstrate that the lysis of TNP-Kd-Dk targets is not due to cross-reactive clones against TNP-Kd-Dd, Kb-Db or Kq-Dq antigens. Inhibition of the TNP-Kd-Dk target lysis by TNP-Kk-matched (Kk-Dd or Kk-Db) as well as TNP-Dk-matched (Kd-Dk) blockers also reveals that this target is lysed by clones directed against shared antigens between Kk-TNP and Dk-TNP, indicating that no cytotoxic response restricted for Dk-TNP only could be detected even after in vivo priming.     

The spatial relationship of the viral and H-2 antigens recognized by anti-viral CTLs

With the use of monospecific rabbit anti-G protein and mouse monoclonal anti-H-2K^k, we have analyzed the spatial relationship of the serologically defined H-2K^k antigens and the major surface glycoprotein (G protein) of vesicular stomatitis virus (VSV) to those antigens recognized by B10.A (k, d) anti-VSV cytotoxic T lymphocytes (CTLs). The ability of monoclonal anti-H-2K^k or rabbit anti-G protein to inhibit specifically the cytolytic activity of B10.A anti-VSV CTLs indicates that the G protein and the H-2K^k molecules are in close proximity to the viral and H-2K^k antigens recognized by the anti-VSV (CTLs. By the method of sequential immunoprecipitation, we also demonstrated that only 10–30 percent of the serologically defined G and H-2K^k molecules are in theG-H-2K ^k complexes.Abbreviations used in this paper Con A Concanavalin A - cpm counts per minure - CTLs cytotoxic T lymphocytes - E: T ratio effector: target ratio - G major surface glycoprotein of VSV - MHC major histocompatibility complex - MOI multiplicity of infection - NP40 Nonidet-P40 - PAGE polyacrylamide gel electrophoresis - PBS phosphate-buffered saline - SaCI Staphylococcus aureus, Cowan I strain - SDS sodium dodecyl sulfate - UV ultraviolet light     

H-2-linked genes determine the level of the primary in vitro anti-Mls response

The level of cell proliferation and interleukin-2 (IL-2) production observed in an anti-Mls mixed lymphocyte reaction between spleen cells from H-2 compatible, Mls incompatible mouse strains is determined by the H-2 haplotype of the mouse combination. Thus, while AKR (H-2 ^k) spleen cells stimulated strong M1s^a responses in H-2^k responder cells, AKR H-2b spleen cells stimulated no or negligible M1s^a responses in responder cells from H-2 ^bmouse strains. This effect was observed at the levels of IL-2 production and cell proliferation. The magnitude of the response observed using F₁ (H-2 ^k/H-2 ^b) responder cells was found to be a function of stimulator rather than responder cells. The poor stimulatory capacity of AKRH-2 ^bspleen cells was also shown not to be due to the loss of the stimulatory Mls ^aallele during the construction of the congenic strain from AKR and C57BL/6 parental strains. Using stimulator cells from a second series of congenic mice, we found H-2 ^b(strain DLLP) again to represent a poorly Mls^a stimulatory H-2 haplotype. In addition, H-2^q (DBA/1) cells displayed very poor Mls^a stimulatory potential while H-2^d (D1.C) cells were efficient Mls^a stimulators. Again the effect was shown to be at the level of the stimulator cells. In toto, our findings indicate that the H-2 ^kand H-2 ^dhaplotypes encode strong Mls^a stimulatory potential while the H-2 ^band H-2 ^qhaplotypes determine poor Mls^a stimulatory potential in primary in vitro responses, measured as cell proliferation and IL-2 production.Abbreviations used in this paper: CTL cytotoxic T lymphocyte - IL-1 interleukin-1 - IL-2 interleukin-2 - MLR mixed lymphocyte reaction - NMS normal mouse serum     

CML typing of serologically identicalH-2 mutants

Cell-mediated lympholysis (CML) reactions were studied among four strains of C57BL/6 (B6) mice carrying mutant alleles (H-2 ^ba ,H-2 ^bd ,H-2 ^bg , andH-2 ^bh ) at thez1 locus in theK end ofH-2 ^b and the original B6 (H-2 ^b ) strain. Cross killing of target cells from lines that had not participated in the mixed lymphocyte reaction (MLR) was extensive, but usually less intense than that of target cells of stimulator cell genotype. The extent of CML crossreactivity could be limited by using cells from F₁ hybrid mice as responders in MLR. In a comprehensive analysis of the cytotoxicity exerted by 20 MLR combinations with homozygous, and 10 MLR combinations with F₁ hybrid responder cells, 19 different CML cytotoxicity patterns were identified, corresponding to at least 19 different CML target specificites. When the number of CML mismatches of each mutant with the originalH-2 ^b was calculated,H-2 ^ba was found to be most distinct fromH-2 ^b ,H-2 ^bs andH-2 ^bd were closest toH-2 ^b , andH-2 ^bh occupied an intermediate position. The validity of this sequence of relatedness is supported by published reports on skin graft survival times and on the interaction of T lymphocytes with virus-infected target cells using cells fromz1 locus mutants.     

Use ofH-2 mutations to quantitate alloreactivity: Alloreactivity is strongest against H-2 antigens which are closest to self

Lymph-node cells fromH-2 allogeneic, intra-H-2 recombinant andH-2 mutant congenic strains were sensitized in limiting dilution cultures to quantitate the cytotoxic T-lymphocyte precursor frequencies (CTL.Pf) against antigens encoded by different regions of theH-2 complex. When fourH-2K ^b mutants of C57BL/6 (B6) were tested, we observed anti-B6 CTL.Pf that were as high or higher than those of recombinant strains which differ from B6 at theK end of theH-2 complex. Relative to strains completelyH–2 allogeneic to B6, the CTL.Pf inH-2 ^bm1,H-2 ^bm3 andH-2 ^bm5 averaged 40–50 percent, andH-2 ^bm8 averaged 140 percent. Recombinant strains B10.A (4R) and B10.D2 (R103), which differ from B6 at theK end of theH-2 complex, averaged 60 percent of the completelyH-2 allogeneic value. Since the mutant and wild-type gene products have no serological and minimal structural differences relative to other alleles atH-2K, these results indicate that the CTL.Pf does not increase with increasing H-2 antigenic disparity between any two strains. Rather, the data suggests that the T-cell receptor repertoire recognizes those H-2 molecules or determinants closest to self.     

Natural resistance of irradiated 129-strain mice to bone marrow allografts: Genetic control by theH-2K region

A major genetic determinant of natural resistance to bone marrow allografts, designated asHh-3, was mapped to theH-2K region. This gene may code for or regulate the expression of cell surface structures selectively expressed on donor hemopoietic cells and recognized by naturally occurring cytotoxic effectors. Resistance was observed as failure of donor cell growth in the spleen of irradiated 129-strain (H-2 ^bc ) recipients of H-2^k bone marrow cells. The mapping was accomplished by substituting donor cells bearingk alleles throughout theH-2 complex with cells of recombinant mouse lines bearingk alleles at definedH-2 regions. The host antigraft reaction underlying resistance was abrogated by pretreating 129-strain mice with either rabbit antimouse lymphocyte serum or the antimacrophage agent silica. Grafting of H-2K^k cells into mice ancestrally unrelated to 129 but sharing theH-2 ^bc or the similarH-2 ^b haplotype, and intoH-2 ^b/k ,H-2 ^k/bc , andH-2 ^k/d F₁ hybrids revealed that resistance was unique to 129 mice, since mice of the other strains, including F₁ hybrids, were susceptible to the grafts. Thus,Hh-3 incompatibility was a necessary but insufficient condition for the manifestation of allogeneic resistance; other genetic factors not associated withH-2 conferred responder status to 129-strain mice and nonresponder status to D1.LP, B10.129(6M), B10, B6, and possibly to F₁ hybrid mice. The possible relationships between allogeneic resistance to H-2^k marrow grafts, hybrid resistance to H-2^k lymphomas, and F₁ hybrid antiparental H-2^k cytotoxicity induced in vitro are discussed.     

H-2 class I loci determine sensitivity to MCMV in macrophages and fibroblasts

Peritoneal (PM) and bone marrow-derived (BMM) macrophages and lung fibroblasts (LF) from inbred, intra-H-2 recombinant, H-2 mutant, and hybrid mice were infected with murine cytomegalovirus (MCMV) under centrifugal enhancement. At the concentration of virus employed, peritoneal macrophages from strains carrying Kd, Kb, D^d, KS and/or D^s, K4 and/or D4 alleles could be infected to a level of 80%–100%, as assessed by viral antigen expression or loss of Fc receptors. Cells lacking these haplotypes and carrying K^k, K^f, D^k, Df, or Db were resistant, yielding levels of infection below 20% . The background (non-H-2) and class II genotype and the S allele did not influence the proportions of cells infected. Furthermore, sensitivity was dominant in the F, progeny of H-2 b x H-2 k and H-2d x H-2 k crosses, and was not compromised by thebm1, bm3, bm10, or bm14 mutations in the al or2 regions of Kb orD ^b. The proportions of cells able to release infectious virus were low, but paralleled the frequencies of viral antigen expression. The class I genotype also determined susceptibility to MCMV infection in BMM and LF, although up to 35% of H-2 k BMM and 46% of H-2 k LF could be infected. The findings are consistent with an association between K and D antigens and a cellular receptor for MCMV on all three cell types.     

Expression of the H-Y Antigen on thymus cells and skin: Differential genetic control linked toK end ofH-2

The strength of the H-Y antigen on thymus cells and on skin was compared in differentH-2-congenic mouse strains using a host-versus-graft reaction popliteal lymph node assay, and skin grafts from males of parental strains grafted to F₁ hybrid females. The results revealed considerable differences in the strength of the H-Y antigen among different congenic strains; these differences demonstrate the effect of theH-2-linked gene on the expression of the H-Y antigen. The linkage withH-2 was also confirmed in tests with segregating F₂ generations. In the strains bearing recombinantH-2 haplotypes, the strength of the H-Y antigen is similar to that of parental strain from which the recombinant received itsK end, and the responsible gene (or genes) map to the left ofI-C. The effect of theH-2-linked gene(s) on thymus cells and skin is different. The gene linked to theK end ofH- 2^b determines a strong H-Y antigen on thymus cells, but a relatively weak H-Y antigen on skin. The gene linked to theK end ofH- 2^k determines a weak H-Y antigen on thymus cells, but a strong H-Y antigen on skin. The gene linked to theK end ofH- 2^d determines a weak H-Y antigen on both thymus cells and skin. Our observations raise the possibility that the structural gene for the H-Y antigen is linked toH-2. Alternative (but not exclusive) explanations invoke regulatory effects ofH-2 on the expression of the H-Y antigen, possibly by means of the control of the cellular andogen receptors.     

Genetic mapping and immunogenetic characterization of theH- 2fb mutation in the mouse

Rejection of tailskin grafts exchanged between two male hybrids of the cross B10.M × B10.RIII(71NS) revealed a mutation in theH-2 ^f haplotype from the B10.M congenic line. Complementation studies with skin grafting and cell-mediated lympholysis showed the mutant, namedH-2 ^fb , to be different from anotherH-2 ^f mutant,H-2 ^fa , and further, that the HH-2 ^fb mutation occurred in theD end of theH-2 complex. Reciprocal skin grafts exchanged between mutant and normal mice were rejected. Hemagglutinating antibody reactive with B10.M cells was raised in the mutant mice. Mutant spleen cells responded weakly, but significantly, to wild-type cells in a mixed lymphocyte culture and in a graftversus-host assay, but no response was seen in the opposite direction. However, cytotoxic effector cells were generated against target cells in both directions in a cell-mediated lympholysis assay.     

Genetic control of contact sensitivity in mice: Effect ofH-2 and nonH-2 loci

The genetic control of delayed-type hypersensitivity in mice was investigated by contact sensitization with picryl chloride. Distribution patterns of contact sensitivity in 11 inbred strains of mice showed significant differences among strains. Comparison of levels of response between congenic-resistant lines and their inbred partners, at 9 to 11 weeks of age, revealed a clear association betweenH-2 haplotype and the magnitude of response. Testing ofH-2 recombinants further suggested the influence of two genes mapping at either end of theH-2 complex. While theH-2K ^d andH-2D ^k alleles were associated with a high response, theH-2K ^k ,H-2K ^b ,H-2D ^d , andH-2D ^b alleles were associated with a low response. Analysis of the ontogeny of response suggested that theH-2 haplotype manifests its effect through the maturation of contact sensitivity. On both the C57BL/6By and C57BL/10Sn backgrounds, theH-2 ^d haplotype was associated with early maturation of response, while theH-2 ^b haplotype was associated with late maturation. Analysis of the response of congenic lines with different genetic backgrounds and of CXB recombinant-inbred lines further revealed the marked effects of yet other genes on this trait.     

Variation of expression of histocompatibility antigens on tumor cells: absence of H-2Kk-gene products from a gross-virus-induced leukemia in BALB.K

The antigenic profile of the K-GV tumor of BALB.K origin, induced by Gross virus and maintained in vitro and in vivo, was investigated by serological and immunochemical methods and techniques of cell-mediated immunity. The H-2K^k-gene products were absent by several criteria: (1) monoclonal antibody and conventional alloantisera directed against the H-2K^k antigenic specificities were nonreactive by direct testing and by absorptions. (2) H-2K^k products could not be precipitated from glycoprotein or protein extracts of the radiolabeled K-GV tumor. (3) Cytotoxic effectors against H-2K^k produced by sensitization in vitro and in vivo failed to kill K-GV target cells. (4) The tumor could neither stimulate BALB.B congenic mice to produce cytotoxic effectors nor specific cytotoxic antibody against H-2K^k-gene products. In contrast, the H-2D^k antigen was readily detectable by all these criteria. These findings therefore describe a tumor which has selectively lost the H-2K-gene products. The K-GV tumor was able to generate Gross-virus-specific CTL, but had greatly reduced susceptibility to lysis by Gross-virus-specific CTL generated by H-2K expressing AKR (H-2 ^k) tumors. These findings have important implications for the associative recognition of tumor antigens and the immune surveillance of virally induced tumors.Abbreviations used in this paper MHS major histocompatibility system - LcH Lens culinaris hemagglutinin - SDS sodium dodecyl sulfate - CTL cytotoxic T lymphocytes - GCSA Gross-virus-induced cell-surface antigen - MuLV murine leukemia virus