High-resolution mapping of a minor histocompatibility antigen gene on mouse chromosome 2

Minor histocompatibility (H) loci are significant tissue transplantation barriers but are poorly understood at the genetic and molecular level. We describe the construction of a high-resolution genetic map that positions a class II MHC-restricted minor H antigen locus and orders 12 other genes and genetic markers within the we-un interval of mouse Chromosome (Chr) 2. An intersubspecific backcross between 10.UW/Sn-H-3 ^b and CAST/Ei, an inbred stock of Mus musculus castaneus, was used for this purpose. A total of 1168 backcross mice were generated, and 71 we-un recombinants were identified. Significant compression of the genetic map in males versus females and transmission distortion of CAST-derived we, un, and A ^w genes were observed. Monoclonal T cell lines specific for two minor H alloantigens, Hd-1^a and Hd2^a, encoded by gene(s) that map to the we-un interval were used to antigen type the backcross mice. The results suggest the Hd-1^a and Hd-2^a antigens are most likely encoded by a single gene, now referred to as H-3b. The determined gene order is we-0.09±0.09-Itp-0.62±0.23-D2Mit77-0.26±0.15[Evi-4, Pcna, Prn-p]-0.26±0.15-Scg-1-0.44±0.19-[Bmp2a, D2Mit70]-0.09±0.09-[D2Mit19, D2Mit46]-1.59±0.36-D2Mit28-0.97±0.28-D2Lerl-1.50±0.35-H-3b-0.26±0.15-un (% recombination±1 SE). Because the average resolution of the backcross is 0.09 cM, the backcross panel should facilitate the physical mapping and molecular identification of a number of genes in this chromosome region.     

Continued mapping of chromosome 2 genes

This report describes our continued efforts to elucidate the genetic fine structure of the central portion of the mouse chromosome (Chr) 2. Mice from our panel of 28 Chr 2 congenic strains were tested: (1) for the presence of the antigens which stimulate Chr 2-reactive lymphocyte clones in mixed lymphocyte reactive lymphocyte clones in mixed lymphocyte reaction (MLR); (2) for the antigens of histocompatibility (H) genes H-42 ^a and H-45 ^a as determined by allograft rejection; and (3) for their ability to respond to the H-Y antigen in a cell-mediated lysis assay. The results obtained in this study have allowed additional mapping of immunoogically involved Chr 2 genes. The gene encoding the antigen which stimulates lymphocyte clone 1C11 can be considered wholly different from other Chr 2 H genes on the basis of chromosomal recombination. We have assigned the symbol H-48 to this gene. The following gene order has been established: [H-3, B2m, pa], we, [H-42, H-48], H-45, IR-H-Y, Hd-1, un, H-13, A ^w. The order of the bracketed genes is not known. H-44 maps centromeric to IR-H-Y. The genes encoding the antigens that stimulate lymphocyte clones 2G7, 2C10, 1F6, 1B10, and 1H10 map centromeric to H-45.     

An H-11-linked gene has a parallel effect on Leishmania major and L. donovani infections in mice

The courses of visceral infection following intravenous injection of Leishmania donovani amastigotes, or lesion growth following subcutaneous injection of L. major promastigotes, were examined in B10.129(IOM) (H-2 ^b, H-11 ^b) mice and compared with disease profiles observed in congenic C57BL/10ScSn(=B10) (H-2 ^b, H-11 ^a) and B10.D2/n (H-2 ^d, H-11 ^a) mice, and in BALB/mice. Possession of alternative alleles at H-11 and closely linked loci transformed the normal curing/healing phenotype of B 10 mice into a characteristically different noncuring/nonhealing phenotype affecting both visceral and subcutaneous infections in B10.129(10M) mice. In reciprocal radiation bone marrow chimeras made between the congenic B10 and B10.129(10M) strains, both cure and noncure phenotypes were transferable with the donor hematopoietic system. Although it was possible to demonstrate transfer of suppression with T-enriched spleen cells from day 61 L. donovani-infected B10.129(10M) donor mice into 550 rad syngeneic recipients, the pretreatment of mice with sublethal irradiation did not, as in the earlier studies of Scl-controlled L. major nonhealing or H-2-controlled L. donovani noncure phenotypes, have a clear or consistent prophylactic effect. Together with the progressive disease profile observed even for L. donovani at low parasite doses this suggests that, despite their ability to develop initial delayed-type hypersensitivity reactions to parasite antigen early in L. major infection, B10.129(10M) mice possess some inherent defect in ability to mount a cell-mediated response effective at the level of macrophage antileishmanial activity in vivo even when suppressor T cells are not generated. Further elucidation of this characteristically different noncuring/nonhealing phenotype may provide important insight into common events involved in the development of the cell-mediated immune response to both visceral and subcutaneous forms of leishmaniasis.     

Identification of a congenic mouse line with obesity and body length phenotypes

Our primary objective was to discover simplified mouse models corresponding to human obesity linkages. We used the B10.UW– H3^b we Pax1^un a^t/Sn (B10.UW) congenic strain, a subcongenic strain with a reduced UW strain donor region, and their C57BL/10SnJ background strain. The congenic and subcongenic UW strain donor regions are on mouse Chr 2. We measured body length [anal-nasal (AN) length], summed fat depot weights normalized for body weight (Adiposity Index, AI), and percentage of body weight that is lipid. The B10.UW congenic and subcongenic strains have significantly smaller AN lengths (p < 0.0001) and have a significantly lower AI and percentage of body weight as fat than the background strain (p < 0.0001). In an F₂ intercross of the congenic and background strains, AN and AI were both linked to the distal half of the donor region with LOD scores greater than 19 and 5, respectively. F₂ haplotypes identified a minimal region for AN linkage of 0.8 megabases (Mb) that is estimated to express four genes in the current Celera mouse genome assembly. We narrowed the most likely location of the obesity gene to 15 Mb whose homologous genes are all located on human Chr 20 in the region surrounding the centromere. Since a previous study identified human obesity linkage peaking near the centromere, then the B10.UW mice may exhibit obesity due to the homologous gene.     

Thirteen new chromosome-7 congenic lines

Thirteen new congenic lines have been produced which have chromosome-7 segments introduced from different strains onto the C57BL/10Sn background. Sublines B10.P(61NX)C,D, and E received chromosome-7 segments from P/J, B10.CE(62NX) from CE/J, B10.SEC(64NX)A,C,E, and F from SEC/1Re, B10.SM(65NX) from SM/J, B10.WB(66NX) from WB/Re, B10.A(67NX) from A/SnGrf, B10.AKR(68NX) from AKR/SnGrf, and B10.K(69NX) from C3H.K. Isograft testing indicated that three sublines, B10.P(61NX)D, B10.CE(62NX)B, and B10.WB(66NX)B are histoisogenic, i.e., histocompatible within each line. With the exception of B10.A(67NX), B10.AK(68NX), and B10.K(69NX), which have not been isografted, the remaining sublines showed residual heterozygosity on isografting. The three histoisogenic lines have undergone F₁ testing and have been found to possess theH-4 ^a allele and new and distinct alleles at theH-1 locus. They have been designated B10.P(61NX)-H-4^a H-1 ^d , B10.WB(66NX)-H-4^a H-1 ^e , and B10.CE(62NX)-H-4^a H-1 ^f . Direct exchange of grafts has indicated the following genotypes: B10.A(67NX)-H-4^a H-1 ^b , B10.AK(68NX)-H-4^a H-1 ^b , and B10.K(69NX)-F-4^a H-1 ^b . The B10.SEC(64NX) and B10.SM(65NX) sublines have not been typed completely forH-4 andH-1. F ₁ testing or direct exchange of skin grafts indicated that B10.P(61NX)-H-4^a H-1 ^d , B10.WB(66NX)-H-4^a H-1 ^e , B10.A(67NX)-H-4^a H-1 ^b B10.AK(68NX)-H-4^a H-1 ^b and B10.K(69NX)-H-4^a H1 ^b possess nonon-H-1 histocompatibility differences from the G57BL/10 background.     

Cell-mediated cytotoxicity to non-MHC alloantigens on mouse epidermal cells

Mice of the C3H/He and A non-H-2 backgrounds are disparate from mice of the B10 background for the tissue-restricted, non-H-2 alloantigen of epidermal cells (EC), Epa-1, that is expressed by EC but not by lymphocytes (LC), as well as for a number of other alloantigens of the B10 background that are expressed by both EC and LC, generically referred to as lymphocyte/epidermal alloantigens (LEA). In this study, we compared the ability of various H-2 congenic strains on the C3H or A backgrounds to mount cytotoxic T-lymphocyte (CTL) responses to EC from H-2 compatible mice of the B10 background. High responses to Epa-1 were detected only in the H-2 ^aand H-2 ^khaplotypes; H-2 ^b, H-2 ^o1, H-2 ^s, H-2 ^t1, and H-2 ^t2 haplotypes were nonresponders to Epa-1. High responses to LEA were detected in H-2 ^a, H-2 ^b, H-2 ^s, H-2 ^t1, and H-2 ^t2 haplotypes; H-2 ^kand H-2 ^o1 were nonresponsive to LEA. Analysis of the H-2K, I and D region alleles of responders indicates that H-2K ^kis essential for anti-Epa CTL responses, whereas D ^d, D ^b, or K ^swere all permissive for strong anti-LEA responses. The ability to mount a given CTL response was not associated with differences in I-region alleles. These results are discussed in terms of K/D region products serving as Ir-gene products for CTL and in determining the apparent tissue-specificity of CTL.     

Histocompatibility genes (theH-2 complex) and susceptibility to spontaneous lung tumors in mice

The incidence of spontaneous lung tumors in relation toH-2, the major histocompatibility complex, was studied in congenic strains of mice on the B10-, A-, and C3H-backgrounds.The most relevant results were obtained with congenic strains on the B10-background. The strains could be divided into two groups: one with a low frequency of spontaneous lung tumors carrying the haplotypesH-2 ^b ,H-2 ^h4 ,H-2 ^d ,H-2 ⁱ H-2 ^r and one with a higher incidence of lung tumors carrying the haplotypesH-2 ^f ,H-2 ^m ,H-2 ^h2 ,H-2 ^a . The differences between these two groups were highly significant.Analysis of the results obtained with the recombinant strains indicated that genes in theIB region determined the susceptibility to the development of spontaneous lung tumors.The comparison of the results in the B10, B10.A and A strain has shown that the incidence in the B10.A strain carrying the haplotypeH-2 ^a derived from the highly susceptible strain A (H-2 ^a ) on the resistant background strain B10 (H-2 ^b ) is intermediate between these two strains. This shows, that other genes of the background are also involved.The lung tumor incidence in (B10.A × B10)F₁ hybrids was intermediate between the two parental strains.The results obtained in the strains C3H with the haplotypeH-2 ^k , C3H.B10 with the haplotypeH-2 ^b and C3H.NB with the haplotypeH-2 ^p , were inconclusive because of the early mortality which occurred among the animals of these strains. The strains A (H-2^a) and A.SW (H-H-2 ^s ) were both equally susceptible.     

The production,testing, and utility of double congenic mouse strains

Two new double congenic strains, B10-H-2 ^a H-7 ^b /Wts and B10-H-2 ^d H-7 ^b /Wts, were selected to differ from B10.A and B10.D2/o, respectively, at theH-7 locus. The survival time ofH-7-incompatible skin grafts is dependent upon theH-2 haplotype of recipient and donor.     

H-2-linked recessiveIr gene regulation of high antibody responsiveness to TNP hapten conjugated to autogenous albumin

The antibody response to the hapten 2,4,6-trinitrophenyl (TNP) conjugated to autogenous mouse serum albumin (MSA) is regulated by anIr gene(s) located within the major histocompatibility complex (MHC). Both the qualitative and quantitative ability of congenic strains to produce TNP-specific antibodies are functions of theH-2 haplotype. Thus, mouse strains may be classified as high (H-2 ^d), intermediate (H-2 ^b,H-2 ^s), and low responders (H-2 ^a,H-2 ^k,H-2 ⁿ,H-2 ^p,H-2 ^q). Antibody responses, as measured by antigen-binding capacities in modified Farr assays, were compared among strains carrying recombinantH-2 haplotypes and their hybrid progenies. Distinct high- and low-responder phenotypes were evident throughout the time course of both primary and secondary antibody responses. The gene locus controlling specific responsiveness to TNP-MSA, now designatedIr-6, was mapped within theI-B subregion of theH-2 complex. Recessive inheritance of high responsiveness was confirmed in hybrid progenies of three different low × high-responder crosses.     

An H-2K gene of the t w32mutant at the T/t complex is a close parent of an H-2K qgene

Two recombinant mice have been recovered from the progeny of Ttf/t ^w32+ animals. They have lost the t^w32 lethality factor(s) and gained tufted, presumably from the T chromosome. Southern blot analysis of class I genes of these two new partial t ^PA027 and t ^PA286 haplotypes indicates that they have retained at least part of the major histocompatibility complex of the t ^w32 chromosome (H-2 haplotype H-2 ^w28). We have prepared a phage library of Eco RI-digested DNA from homozygous t ^PA027 animals. Upon screening the library with a cDNA probe specific for H-2K genes, we isolated a class I gene displaying all of the distinctive features of a genuine H-2K gene, and which could thus be defined as an H-2K ^w28 gene. The H-2K ^w28 gene is 92–95% homologous to H-2K ^band H-2K ^dgenes and differs significantly from the other class I genes sequenced so far. Homology with the H-2K ^bsequence reaches nearly 100% in the 3 part of the H-2K ^w28 gene. Moreover, the homology with an H-2K ^qcDNA sequence reaches 99.8%. Several hypotheses can account for the near identity of H-2K ^b, H-2K ^q,and H-2K ^w28 gene sequences: either recombination between H-2 ^w28 and H-2 ^band H-2 ^qsequences occurred before or at the.time the strain was established, or the class I genes of the t ^w32 chromosome and the H-2 ^band H-2 ^qgenes found in inbred strains of mice have separated from each other rather recently.     

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.     

Responses against antigens encoded by theH-3 histocompatibility locus: Antigens stimulating class I MHC- and class II MHC-restricted T cells are encoded by separate genes

The purpose of this work was to study the genetic basis of histocompatibility antigens encoded by the mouse minor histocompatibility (H) locusH-3. Both class I major histocompatibility complex (MHC)-restricted cytotoxic T lymphocytes (CTL) and class II MHC-restricted helper T cells (TH) specific for antigens encoded by genes within theH-3 locus were isolated and analyzed. Typing a number of mouse strains for expression of antigens recognized by these TH and CTL suggested that there was a different strain distribution pattern of expression of the antigens recognized by TH compared with those recognized by CTL. Separation of the genes whose products stimulate TH from those whose products stimulate CTL was suggested by: (1) analysis of the strain B10.FS(92NX)/Grf that has undergone recombination within theH-3 region; (2) genetic segregation studies of (B10.UW-H-3 ^b/Sn×C57BL/10Sn)F₂ mice; and (3) F₁ complementation studies in which CTL specific for products of the TH-defined gene(s) could not be detected, even in the absence of immune responses to products of the CTL-defined genes. Taken together, these data suggest that in addition to two genes (B2m andCd-1) within theH-3 region whose products typically stimulate class I MHC-restricted CTL, there is at least one additional gene whose product selectively stimulates class II MHC-restricted TH. This new gene is located telomeric from the CTL-defined genes and between the lociwe andun on chromosome 2. These data demonstrate a novel degree of complexity of theH-3 “locus” and suggest selective presentation of minor H gene products in the context of class I or class II MHC proteins.     

The effect of water activity on growth and end-product formation of two Lactobacillus spp. and Brochothrix thermosphacta ATCC 11509T

Summary The effect of water activity (a_w) on the growth and end-product formation of Lactobacillus viridescens SMRICC 174, Lactobacillus SMRICC 173 (homofermentative) and Brochothrix thermosphacta ATCC 11509^T was studied. All strains orginated from meat or meat products. The a_w was adjusted in the range 0.94–0.99 with NaCl or glycerol. A greater reduction in growth rates was found for L. viridescens and B. thermosphacta when a_w was regulated with NaCl rather than with glycerol, the opposite was true for Lactobacillus 173. L. viridescens grew at a_w >-0.94. At 0.94 a_w B. thermosphacta was totally inhibited when NaCl was the solute and Lactobacillus 173 when glycerol was the solute. Only minor variations in the end-product formation of the Lactobacillus spp. were found at different a_w values. In aerobic culture B. thermosphacta produced less l-lactic acid and more acetic acid as the a_w was decreased with NaCl, while the yields were unaffected when glycerol was used.     

Histocompatibility-2 system in wild mice

Six semicongenic lines carrying differentt haplotypes on the background of strain C57BL/10Sn (B10.t strains) and a (B10 ×T/t ⁰) F₁ hybrid were tested against one another in the mixed lymphocyte reaction (MLR) and cell-mediated lymphocytotoxicity (CML) assays. In every instance, the MLR results paralleled those of the CML typing: strain combinations giving a positive result in one assay gave a positive result in the second; combinations in which no response was observed in the MLR assay also failed to kill target cells specifically in the CML assay. Furthermore, the MLR and CML results were concordant with the results of the serological typing of these strains, as reported previously by us. The combined results suggest sharing ofH-2 hyplotypes between B10.t¹² and B10.t³², between B10.t⁶ and B10.t^w1, and between B10.t^w2 and (B10. ×T/t ⁰) F₁. These data support the conclusion, reached in our previous publication, that members of the samet-complementation group, with few exceptions, shareH-2 haplotypes.     

Glucocorticoid-Induced Cleft Palate in the Mouse: Two Major Histocompatibility Complex, H-2, Loci with Different Mechanisms

Isolated cleft palate is induced in the progeny of pregnant mice that are given glucocorticoids. The incidence varies among inbred strains and with dose and stage of gestation when the drug is given. One chromosomal region responsible for strain-associated differences in sensitivity is the major histocompatibility complex, H-2. H-2^a is associated with susceptibility, H-2^b with resistance. There appear to be both maternal and embryonic genetic factors affecting the sensitivity to glucocorticoids. In experiments reported here congenic strains of mice with H-2^a, H-2^d and H-2^k haplotypes on a C57BL/10 genomic background were used. This allowed the determination of the effect on sensitivity by two H-2 subregions; the subregions are H-2K to I-E and I-C to H-2D. Methods included dose-response analysis and reciprocal cross analysis using dexamethasone given on day 12 of pregnancy. Results show that each subregion affects the strain's sensitivity to dexamethasone-induced cleft palate. The regression coefficients for B10.A-H-2^a (45.4 ± 4.13) were different from those for B10.BR-H-2^k (67.2 ± 10.8) and B10.D2-H-2^d (70.5 ± 9.74). The estimated mean arcsine% cleft palate at 160 mg/kg was different for each strain: B10.A- H-2^a, 53.1 ± 2.19; B10.BR-H-2^k, 33.1 ± 2.27; B10.D2-H-2^d, 25.0 ± 2.75. Different patterns of change in sensitivity were observed among the reciprocal crosses. In summary, the H-2K to I-E subregion seemed to influence both maternal and embryonic factors, whereas only embryonic factors were influenced by the I-C to H-2D subregion. These data suggest that the mechanisms affecting glucocorticoid sensitivity which are genetically encoded within each H-2 subregion are different, and there is an interaction between the alleles. The mode of interaction can be either complementation or epistasis.     

Recombination between two mouse t haplotypes (t w12 tf) and t Lub-1) : Mapping. of the H-2 complex relative to centromere and tufted (tf) locus

A monoclonal antibody known to recognize the H-2.m3 specificity is shown to react with the class I H-2 product of t ^Lub-1 but not t ^w12 tf mice. This reagent was used to study the segregation of the H-2 complex in the progeny of t ^Lub-1 +/t ^ww12 tf females. The most straightforward interpretation of the results presented here is that these t haplotypes carry an H-2 complex located between the centromere and tufted locus. Possible consequences of such a location with regard to the recombination between t haplotypes and chromosome 17 from laboratory mice are discussed.     

TheH-2 class II genes and the susceptibility to the development of pulmonary adenoma in mice

To determine the locus in theH-2 complex that affects susceptibility to the development of pulmonary adenomas in mice,H-2 congenic and recombinant strains of mice with A/Wy, BALB/c, C3H, and B10 backgrounds were subjected to treatment with urethane. The average number and the incidence of adenoma foci were recorded five months after the treatment. InH-2 congenic strains on the A/Wy background, the average number of adenoma foci per mouse was significantly higher in mice of the A/Wy, A/J, and A-Tla ^b (H-2 ^a ) strains than in A.BY (H-2 ^b ) mice. In BALB/c and C3H congenic strains, the strains carrying theH-2 ^k haplotype were more susceptible than those carrying theH-2 ^b haplotype. InH-2 congenic strains on the B 10 background, the average number and incidence of foci was also higher in haplotypesa, h2, k, andj than in haplotypesb, s, f, d, r, h4, i3, i5, and4. The average numbers of adenoma foci in (A/J × A.BY)F₁ (H-2 ^a /H-2 ^b ) and (B10 × B10.A)F₁ (H-2 ^b /H-2 ^a ) were intermediate between the numbers in the parental strains. In [B10.A (4R) × B10.A (3R)]F₁ (H-2 ^h4 /H-2 ⁱ³ ) and [B10.A (4R) × B10.A (5R)]F₁ (H-2 ^h4 /H-2 ⁱ⁵ ), the numbers of adenoma foci were higher than in resistant parental recombinants. These patterns of response to urethane matched the patterns of the immune response to lactate dehydrogenase-B (LDH-B) and immunoglobulin gamma 2a (IgG2a) proteins. These differences between mice in their susceptibility to the development of pulmonary adenomas is probably due to the polymorphism of the class II genes in theH-2 complex.     

Genetic control of acquired resistance to visceral Leishmaniasis in mice

A series ofH-2 and non-H-2 congenic resistant (CR) strains on a C57BL/10Sn background were infected with 10⁷ amastigotes ofLeishmania donovani. Non-H-2 congenic strains B10.LP-H-3 ^b and B10.CE(30NX) and (B10.LP-H-3 ^b × B10)F₁ hybrids showed a very rapid decrease in liver-parasite burdens beyond day 21. Parasite counts for these strains at day 35 were significantly lower than for all other strains tested. The rapid decrease in parasite numbers, massive lymphocellular infiltration into the liver and strong delayed hypersensitivity reactions to parasite antigens in strains congenic for a portion of chromosome 2 indicated that acquired immunity toL. donovani was controlled by a dominant gene at or near theIr-2 locus. In addition, B10.129(10M) mice, which differ from C57BL/10Sn at theH-11 locus, showed highly significant increases in parasite numbers at day 35. Other observations supporting the absence of acquired immunity in B10.129(10M) included negative delayed hypersensitivity tests to parasite antigens and the absence of lymphocellular infiltrate into the liver. Although the differences were not as pronounced,H-2 CR strains withH-2 ^b ,H-2 ^a , andH-2 ^k haplotypes also showed significantly greater decreases in parasite numbers by day 35 as compared to otherH-2 CR strains.     

Hierarchy ofH-2 haplotypes governs inheritance of immune responsiveness to TNP-MSA

Production of indirect TNP-specific plaque-forming cells (PFC) in response to immunization with 2, 4, 6-trinitrophenyl (TNP) conjugated to autogenous mouse serum albumin (MSA) in complete Freund's adjuvant (CFA) is underH-2 control. On the C57BL/10 (B10) background,H-2 ^b andH-2 ^d strains of mice are high responders, whereasH-2 ^a ,H-2 ^k orH-2 ^y2 strains yield low levels of indirect TNP-specific PFC. An unusual pattern of inheritance has been revealed in B10 congenic mice: high responsiveness controlled byH-2 ^b is inherited recessively, while high responsiveness controlled byH-2 ^d is inherited dominantly. On the C3H and A strain backgrounds, high responsiveness controlled byH-2 ^b is partially recessive;H-2 ^b /H-2 ^a F₁ mice respond with 20%-40% of the high responderH-2 ^b response. Yet, high responsiveness controlled by theH-2 ^d haplotype remains dominant on the C3H background. A hierarchy of haplotypes in order of decreasing immune responsiveness to TNP-MSA is evident as follows:H-2 ^d >H-2 ^b >H-2 ^k ,H-2 ^a orH-2 ^y2 . The unusual patterns of inheritance in the TNP-MSA system reveal graded regulation of responsiveness attributable to bothH-2 and non-H-2 genes.     

MHC recognition by clones of Mls specific T-lymphocytes

To test whether M1s determinants, like other non-MHC or nominal antigens, are recognized by T-cells in association with H-2 determinants, the in vitro proliferative responses of T-cell lines and clones were studied. Lines and clones were prepared by soft agar cloning (B10.BR x BALB/c)F₁ (H-2^k/H-2^d, M1s^b/M1s^b) T-cells responding in a primary MLR to AKD2F1 (H-2^k/H-2^d, M1s^a/M1s^a) stimulator cells. All the T-cell clones obtained could respond equally well in a proliferative assay to the Mls^a determinant in association with the H-2 haplotype of either parent, i. e., DBA/2 (H-2^d, M1s^a), and AKR (H-2^k, M1s^a) both stimulated equally well. When the T-cell lines and clones were screened against stimulators from recombinant inbred (RI) strains, it became apparent that strains exhibiting the H-2^b, M1s^a genotype stimulated poorly or not at all. This shows that the T-cell response to M1s^a involves MHC recognition, and raises the possibility that the response to M1s^a can involve recognition of H-2 specificities shared between the H-2 ^k and H-2 ^d haplotypes.Abbreviations used in this paper MHC major histocompatibility complex - MLC mixed lymphocyte culture - IL-2 interleukin 2 - Con A concanavalin A - RI recombinant inbred Howard Hughes Medical Institute