Mapping of susceptibility to Marek's disease within the major histocompatibility (B) complex by refined typing of White Leghorn chickens.

The major histocompatibility (B) complex of a distinct commercial pure White Leghorn chicken line was characterized using serological, biochemical and restriction fragment length polymorphism (RFLP) typing. Line B chickens displayed a high recombination frequency within the B complex. Three recombinant haplotypes were identified. The influence of these haplotypes was determined in relation to the haplotypes B19 and B21 on their resistance to Marek's disease (MD) in an experimental infection with the virus. Offspring of sires with a recombinant haplotype in combination with B19 or B21, and dams, which were homozygous B19/B19 or B21/B21 were infected. The B type of the offspring had a significant effect upon survival. Animals with B complex types B21/B21, B134/B21 and B234/B21 were relatively resistant to MD (24-32% mortality), whereas B19/B19 birds were highly susceptible (68% mortality). Animals with a recombinant haplotype B19r21 (B-G21, B-F19) were equally susceptible to MD as birds with the complete B19 haplotype. In contrast to earlier publications, resistance was not inherited as a dominant trait. Apparently, B19 was associated with a dominant susceptibility. The gene(s) associated with the B complex and involved in resistance to MD were localized within the B-F/B-L region. However, the association with a presumably non-coding subregion of B-G could not be excluded.

The effect of serologically defined major histocompatibility complex haplotypes on Marek's disease resistance in commercially bred White Leghorn chickens.

In commercial pure white leghorn lines, A, B, and C, the effects on resistance against a virulent strain of Marek's disease virus were assessed for B19 and B21 haplotypes of the chicken major histocompatibility complex. B haplotypes were identified by direct hemagglutination using alloantisera raised against erythrocyte antigens. In homozygous B21 female chicks from lines A and B, mortality upon challenge with virus was 16% and 9%, respectively; in B19 chicks, mortality was 42% and 60%, respectively. Intermediate mortality was observed in heterozygous B19/B21 birds. When line A and B hens were crossed with B15/B15 or B5/B19 cocks from line C, differences between B19 and B21 were significant only in the progeny from B5/B19 sires. Therefore, it was concluded that selection for major histocompatibility complex-associated disease resistance markers may be useful only when B haplotypes complement each other in commercial line crosses and when interactions with genetic background do not severely obscure the differential haplotype effects, as are observed within pure lines.

Role of the endothelial antigen Eag-1 in the rejection of rat kidney allografts.

The immunogenicity of the minor histocompatibility antigen Eag-1 of the rat kidney endothelium was studied in renal allografts mismatched for antigens of the major histocompatibility complex (MHC). The rejection rates of BN.1L (RT1(1), Eag-1+), (BN.1LXMAXX)F1 (RT1l/n, Eag-1+), and LEW (RT1l, Eag-1-) kidneys transplanted into unsensitized, bilaterally nephrectomized MAXX (RT1n, Eag-1-) recipients were comparable, indicating that incompatibility for Eag-1 has no effect on the survival of MHC-incompatible kidney grafts. Transplantation of BN (RT1n, Eag-1+) and WKY (RT1k, Eag-1+) kidneys into unilaterally nephrectomized MAXX recipients led to a weak and inconsistent antibody response against Eag-1, indicating that MHC incompatibility does not influence the formation of antibodies against Eag-1.

Immunogenicity of the non-MHC-encoded endothelial antigen Eag-1 in various tissues of the rat.

Immunizations of MAXX rats with spleen and lymph node cells from BN donors lead to the production of antibodies against the renal endothelial antigen Eag-1. In the present study we analyzed the ability of various tissues to induce a response against Eag-1. Lung homogenates, like spleen and lymph node cells, induced a strong and rapid antibody response. A weak and slow response was induced by cardiac allografts as well as kidneys transplanted into recipients in which unilateral or delayed bilateral nephrectomy was performed. Transplantation of kidney or skin allografts into intact recipients did not result in the formation of Eag-1 antibodies, nor did immunizations with kidney homogenates. A rapid response, however, was observed after transplantation of BN kidneys into MAXX rats previously sensitized by a single injection of BN lymphoid cells, whereas no secondary response was induced by BN kidney homogenates. With an indirect immunofluorescence technique, Eag-1 was detected on lung and kidney endothelium, but not on lymphoid cells or heart and skin tissue. It thus appears that the immunogenicity of Eag-1 does not correlate with the quantitative expression in different tissues and that lymphoid cells, rather than vascular endothelial cells, can induce a strong and rapid response against Eag-1. Because the immunogenicity of lymphoid cells was diminished by heat treatment and freeze-thaw lysis, it appears that intact donor cells are required for the stimulation of antibody production.

Genetics of the antibody response to an endothelial transplantation antigen in the rat.

Immunization of MAXX (RT1n) rats with pooled spleen and lymph node cells from the BN (RT1n) strain results in the formation of alloantibodies against a nonmajor histocompatibility complex (MHC) encoded transplantation antigen on peritubular capillary and venous endothelium of the kidney. Since ACI (RT1a) strain animals did not respond to the antigen, the genetics of the in vivo humoral immune response to repeated immunization were investigated in 43 animals of the second filial generation from the responder MAXX and the nonresponder ACI strain, as well as in 13 animals produced by backcrossing (MAXX X ACI)F1 and ACI. Because 38/40 RT1n-positive animals responded, while 16/16 RT1a/a recipients did not, it was shown that the RT1n haplotype was required for responsiveness. Using the intra-MHC recombinant strains DA.1I (RT1.AnBaDaEu) and WRC (RT1.AnBnDa), the immune response was mapped within the class II region of the MHC-complex. Effects of MHC-(in)compatibility between donor and recipient on the response were ruled out, since MAXX rats formed endothelial antibodies upon immunization with the MHC-incompatible BN.1L (RT1(1), BN.1A (RT1a), and WKY (RT1k) cells, whereas ACI animals failed to produce endothelial antibodies after immunization with BN.1A cells. Furthermore, the response appears to be thymus dependent because congenitally athymic WAG/rnu (RT1u) rats failed to produce endothelial antibodies, in contrast to the euthymic WAG/Rij (RT1u) strain.

Linkage of loci encoding a kidney endothelial antigen and fumarate hydratase (Fh-1) in the rat.

In the rat a single locus, provisionally designated Eag-1, controls the expression of an antigen present on the endothelium of kidney peritubular capillaries and veins. We have examined the linkage relationship between Eag-1 and 10 polymorphic loci including hemoglobin b, fumarate hydratase, peptidase-3, urinary pepsinogen, seminal vesicle protein, glycerophosphate dehydrogenase, esterase-1, esterase-6, pinkeye, and hooded. Tissue samples from animals derived from (AUG X BN.1C)F1 X AUG and (AUG X BN.1C)F1 X BN.1C backcrosses were examined and a linkage association between Eag-1 and Fh-1 (EC 4.2.2.1) was detected. The linkage distance between Eag-1 and Fh-1 is 21 cM (chi 2 = 27.9; p = 0.00001) and this association defines the third locus in the tenth (X) linkage group of the rat.

A novel alloantigen on rat macrophages and granulocytes.

Previous studies have shown that immunization of MAXX rats with spleen and lymph node cells from the MHC-identical BN strain results in the formation of antibodies that react with the renal endothelial alloantigen Eag-1. In the present study, the reactivity of MAXX anti-BN sera was further characterized. No reactivity of the antisera was detected with unseparated spleen, lymph node, thymus and bone marrow cell suspensions, peripheral blood, or cells obtained from lung lavages. The antisera did, however, react with splenic macrophages, as well as with peritoneal granulocytes and macrophages from BN, BN.1A, BN.1L, and PVG rats. Genetic studies revealed that the antigen, provisionally designated Pag-1, segregates independently of Eag-1, the RT1 complex, sex, and the hooded and albino traits. Pag-1 appears to be absent in the kidney, since absorption of MAXX anti-BN sera with BN kidney homogenates did not remove the reactivity against Pag-1, and antisera raised against BN peritoneal cells did not bind with the renal endothelium. Pag-1 is expressed on bone marrow-derived cells, since peritoneal cells from lethally irradiated MAXX rats that were reconstituted with bone marrow cells from BN donors reacted with MAXX anti-BN sera, whereas peritoneal cells from BN rats reconstituted with MAXX bone marrow did not.

Influence of non-H-2 genes on the in vivo response to penicillin-treated autologous platelets.

Mice of different inbred strains were injected intravenously on day 0 and day 6 with autologous platelets incubated in a penicillin solution. After the second injection mice of most strains died immediately with anaphylactic symptoms. Both passive transfer experiments and indirect immunofluorescence studies suggest that a serum factor (probably IgM) is involved in this phenomenon. Only mice with a C3H background were unable to respond to autologous penicillin-treated platelets, although C3H platelets did induce a lethal response in B10.A mice. Experiments in which B10.A mice were primed with autologous penicillin-treated platelets and rechallenged with allogeneic penicillin-treated platelets, showed that the response is directed against a polymorphic non-H-2 antigen in combination with penicillin.

Platelet transfusions can induce transplantation tolerance.

Recently we have shown that the induction of antibodies against the H-2 antigens after multiple platelet transfusions is due to leukocyte contamination of the platelet suspensions. Pure platelets are not able to induce a primary antibody response. The present study shows that the platelets, however, can be recognized by the immune system but they induce a suppression of the response. Mice pretreated with donor platelets will not give a primary antibody response upon a subsequent injection of donor leukocytes and the survival of donor skin grafts will be prolonged. Similar results were obtained by pretreatment of the responder mice with heat-treated donor leukocytes. Furthermore, repeated injections of heat-treated leukocytes of the recipient strain to the donor before bone marrow grafting, will delay graft-versus-host mortality. These data show that cells which have only class I antigens on their surface and no activating class II antigens, induce a suppression of the response against class I antigens.