Immunogenetic considerations in islet transplantation: the role of Ia antigens in graft rejection.
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Publications and source records attributed to F H Bach.
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In certain donor-recipient mouse strain combinations with class I (H-2 K, D, and K + D) or with classes I and II (H-2 D + I) disparities the incidence of islet allograft rejection is low. Furthermore pancreatic islet allografts transplanted between strains with class II (H-2 Ia) differences alone are rarely acutely rejected. In this experiment the ability of donor strain or third-party allogeneic splenocytes (active immunization) to induce rejection of established (greater than 100 days) islet allografts when the donor and recipient differed only for class I or class II antigens was tested. Class I disparate islet allografts are rejected if challenged with donor or third-party allogeneic splenocytes. The frequency of rejection is similar (80-89%) if the third-party splenocytes share the class I allele with the islet donor strain. In contrast, class II disparate islet allografts are not rejected after challenge with donor splenocytes or third-party splenocytes even when the third-party strain shares the class II disparity with the islet donor strain as well as class I antigens common to the donor and recipient. Furthermore, rejection of class II disparate islets did not occur following passive transfer of recipient strain splenocytes sensitized in vitro to donor strain lymphocytes. These results show that rejection of established islet allografts can only be induced if (1) the islet graft expresses H-2 K or H-2 D gene products that are different than the recipient strain, i.e., only class I antigens can serve as targets; and (2) challenging splenocytes also have class I disparities with the recipient.
T lymphocyte clones were derived by micromanipulation from an MLC between a stimulator and responder matched for class I but mismatched for class II HLA antigens; among the possible stimulating antigens were DR4 and Dw4. Two of the clones, when tested for cytotoxicity on a panel of DR4 positive and negative targets, appeared to recognize a determinant closely associated with Dw4, but did not lyse, with one exception, targets expressing other DR4 associated Dw specificities or DR4 negative targets. Blocking studies, using monoclonal antibodies directed against monomorphic epitopes on class I or class II molecules, revealed that the cytotoxic activity of these clones was strongly inhibited by an anti-class II (L-243) but not by an anti-class I (w6/32) monoclonal antibody. Both clones were T3+, T4+, T8-. These findings show that cytotoxic T cell clones, (directed against class II antigens), may have specificity that correlates with a T lymphocyte-defined LD/Dw determinant. The blocking experiments using monoclonal antibodies give further support to the idea that these clones recognize determinant(s) on a class II molecule. The cell surface phenotyping results are in agreement with previous reports that most anti-class II cytotoxic clones have a T4+ T8- phenotype.
Various functionally distinct human T cell clones derived from in vitro mixed leukocyte cultures are found to secrete lymphokines with detectable Interleukin-2 (IL-2)-like activity upon antigenic stimulation. These lymphokine producing clones are not only dependent on exogenous growth factors provided in the form of crude phytohemagglutinin (PHA)-induced spleen conditioned medium for growth but can themselves be driven to proliferate by their own lymphokines. The induction of lymphokine production appears to be antigen-specific and the lymphokines secreted are believed to contain nonantigen and nonspecies specific IL-2-like activity. We show here that IL-2-like lymphokines are produced by a subset of T lymphocyte clones, i.e., the help-independent cytotoxic T cells clones that have the capacity to proliferate to, as well as to lyse, the original sensitizing cells. In addition, other T cell clones capable of producing active lymphocytes include those clones that have the T helper cell characteristics, i.e., can undergo antigen-induced proliferation but are not cytotoxic; in the presence of lectin (PHA), however, some helper T cells (Th) but not others, can express lectin-dependent cell-mediated lysis. Finally, yet another subset of T lymphocytes, the help-dependent cytotoxic T cell clones that cannot proliferate to antigenic stimulation, was found to produce no detectable IL-2-like activity.
HLA-Dw2 and Dw12 are both associated with HLA-DR2; however, these specificities accounts for only 86% (161/188) of the DR2+ haplotypes in our North American Caucasian panel. In an attempt to identify new DR2 associated antigenic clusters, we have generated four primed lymphocyte (LD) typing (PLT) reagents in haploidentical familial combination against DR2+ Dw blank haplotypes. These reagents were positively restimulated by 11 of 16 DR2+ Dw blank cells tested, with good discrimination from Dw2 and Dw12+ cells, thus identifying a new antigenic cluster provisionally termed LD-MN2. We have compared the LD-MN2 specificity with the specificity LD-5a defined by two DR2+ HTCs, BAS and REM, (Layrisse, Caracas) which have been included in the pre-1984 Workshop Cluster DB9. Although none of our DR2+ cells gave typing responses to these two HTCs defining LD-5a, PLT studies did indicate an interrelationship between these specificities and with the specificity tb24 defined with the HTC, FJO (Betuel). The LD-5a HTCs, four LD-5a heterozygous cells, and two additional HTCs (WJR-Hansen, Seattle and FJO/tb24--Betuel, Lyon) significantly restimulated the anti-MN2 PLT reagents, though usually not as strongly as the MN2+ cells. MN2+ cells primed against the LD-5a HTCs were restimulated by only the LD-5a+ cells. Dw2+ cells primed against FJO were restimulated by some, but not all MN2+ cells. These results suggest that MN2, tb24, and LD-5a share some determinants, not shared with most cells which type as Dw2 and Dw12, though differing by other stimulatory determinants. These studies emphasize the necessity of studying new antigenic clusters by both PLT and HTC methodologies as well as testing different ethnic groups.
Variants of a lymphoblastoid cell line, LCL 526 (SB3 MB1 DR1 B44 C5 A2/SB4 MT4 DR4 B27 C2 A24), which lost various HLA specificities were selected with monoclonal antibodies and complement using a method developed by Kavathas et al. (PNAS 77:4251, 1980). Using alpha B27 monoclonals, 8 B27 only loss mutants and 4 B27 haplotype multiple loss mutants were generated. The parental LCL 526 and two of the B27- mutants were used to select alpha B27 CTLs. The selection of six A2 loss, one A2-C5 loss, and 14 A2 haplotype multiple loss variants as well as secondary selection on haplotype loss variants to obtain A null, B null, DR null, and total A, B, C, null variants is also described. The usefulness of these mutants for the study of the relationship between B27 and disease and as two new haplotypes for immunologic, genetic, and molecular research is discussed. These mutants are available to other researchers.
Recipients of marrow grafts from HLA-identical, (including MLC non-reactive) sibling donors have a 40-50% incidence of acute graft vs. host disease (GVHD); the involvement of non-HLA linked, minor histocompatibility antigens (miHA) has been implicated. One of the target tissues of GVHD is the skin where morphological analysis of biopsy specimens is often used to support this diagnosis. We have obtained skin biopsy specimens from the site of GVHD lesions, grown the cells in the presence of T cell growth factor (TCGF) and feeder cells, and tested these cultured cells in the primed lymphocyte test (PLT) and cell mediated lympholysis (CML) assay. Five of six cell cultures tested demonstrated secondary proliferative but not cytolytic reactivity; cells from one culture demonstrated both reactivities. The cell culture populations generated are presumably directed against non-HLA antigens, i.e., miHA whose expression is restricted by an HLA antigen of the recipient. The data are consistent with the suggestion that in the majority of these cultures, the restriction element may be a determinant encoded within the HLA-D region: DQ, DR, and possibly DP based on panel testing. Although the number of cases is small, these preliminary data demonstrate the feasibility of this type of culturing system and also suggest that the cellular immunological events leading to the manifestation of skin GVHD lesions may be predominantly a delayed type hypersensitivity reaction.
Cloning of cells allosensitized in vitro against SB1, SB2, and SB3 antigens was performed by micromanipulation. One hundred and twenty-six clones were tested for both proliferative and cytolytic responses; 14 proliferative, noncytotoxic clones and one clone which demonstrated both proliferative and cytotoxic reactivity specific for SB antigens were obtained. The proliferative noncytotoxic clones tested and the clone with both cytotoxic and proliferative activity were all able to produce IL-2-like activity upon specific antigen stimulation in vitro and were positive for OKT3, OKT4 but negative for OKT8. The proliferative clones fit the characteristics of helper T cell (Th) clones while the clone with both cytotoxic and proliferative reactivities is analogous to the class of antigen-driven, helper cell-independent cytotoxic (HITc) clones. No cytolytic nonproliferative SB specific clones were detected. The prevalent induction of Th clones strongly suggests that the biological function of SB antigens is similar to other class II antigens of HLA. The existence of an SB specific HITc clone demonstrates that a determinant on an SB molecule can induce both proliferative and cytolytic responses.
Following secondary stimulation of mixed leucocyte culture (MLC) populations with a class I plus II HLA difference, antigen-specific suppressor-effector cells of the OKT8+4- phenotype are generated. On the other hand, stimulation with a class II HLA genetic difference only gave rise to OKT4+ suppressor T cells. These effector cell populations which were maintained as "lines" by the addition of exogenous T cell growth factor (TCGF) and feeder cells, mediated antigen-specific suppression over a 6-8 week period during which they were assayed. The data reported here demonstrate that the phenotype of suppressor cells, generated in allogenic MLC, depends on the nature of the class of HLA antigen recognized as disparities in the suppressor-generating MLC. Moreover, both OKT8+4- and OKT4+ suppressors, obtained following stimulation with class I plus II or class II genetic disparities, respectively, appear to be specific for DR (or related class II product) antigens.
In 1968 a 2-year-old boy with Wiskott-Aldrich syndrome was extremely ill with eczema, a series of life-threatening infections, and repeated hemorrhages into his skin, lungs, brain, and other internal organs. He was given high-dose cyclophosphamide therapy for immunosuppression, followed by bone marrow cells from his histocompatible, healthy sister. In the 15 years since bone marrow transplantation, he has had full T cell, partial B cell, and no hematopoietic engraftment. He has weathered the usual infectious diseases of childhood, has had no serious infections, and despite persistent thrombocytopenia has not had serious bleeding episodes.
B cell crossmatches were performed at cold (4 C) and warm (22 C and 37 C) temperatures on 193 renal allograft recipients with negative T cell crossmatches to their donor; 152 of the patients were also tested for autoantibody to autologous B cells. Fifty-six (29%) had a positive B cell crossmatch (21 cold, 35 warm); 14 were autoantibody positive, 23 autoantibody negative, and 19 were not tested for autoantibody. There were no differences in HLA-A, B, C, or DR antigen disparity between the B cell positive (14, 0 DR mismatch; 25, 1 DR mismatch; 9, 0 DR mismatch) and the B cell negative group (40, 0 DR mismatch; 57, 1 DR mismatch; 13, 2 DR mismatch). Similarly, age, diabetic status, and number and type of pretransplant blood transfusions were comparable between B cell positive and negative groups. Although there were no hyperacute rejections, 2-year actuarial graft survival was significantly lower in the B cell positive group, regardless of donor source, graft number, or temperature of reaction. Patients with a positive B cell crossmatch, presumably due to demonstrable autoantibody, may have better graft survival rates than patients with a positive B cell crossmatch and no autoantibody.
Reciprocal transplantation of D-region-histoincompatible thyroid grafts between mice of the B10.S and B10.S(7R) strains resulted in acceptance of all B10.S thyroid grafts by B10.S(7R) recipient mice and acute rejection of 93% of the thyroid grafts in the opposite direction. Evidence of expression of D region gene products on the surface of cells of B10.S thyroid grafts was supported by acute second-set rejection of B10.S thyroid grafts by B10.S(7R) recipients preimmunized with a B10.S skin graft. In vitro analysis of reciprocal immune responses between B10.S and B10.S(7R) mice demonstrated that the unidirectional thyroid graft rejection correlates with a relatively high frequency of cytotoxic T lymphocyte precursors (CTL-P). The frequency of B10.S splenic CTL-P reactive with B10.S(7R) (1/1131) was similar to that against the entire H-2 difference (i.e., B10.S anti-B10.BR, 1/776). However, B10.S anti-B10.S(7R) CTL-P frequency was about 5-fold higher than the reciprocal CTL-P frequency of B10.S(7R) anti-B10.S. The correlation between the high CTL-P frequency and the ability to reject thyroid grafts, as well as possible causes for the difference in the reciprocal CTL-P frequencies are discussed.
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It has been shown that peritoneal exudate cells (PEC) from BALB/c mice immunized with minor histocompatibility antigens presented by DBA/2 or B10.D2 spleen cells are capable of lysing syngeneic YC8 tumor cells in a 4-hr 51Cr-release assay. In this study, we employed limiting dilution analysis to determine the frequency of CTL precursors (CTL-P) reactive against both the specific DBA/2 (or P815) target and the syngeneic tumor YC8. The mean frequency of anti-DBA/2 CTL-P in PEC from BALB/c mice immunized with DBA/2 was 1/302. Between one-third and one-fifth of limiting dilution microcultures that exhibited lytic activity against DBA/2 lymphoblasts (or P815) were also able to lyse YC8. No lysis of YC8 was observed in the absence of a parallel lysis on DBA/2 lymphoblasts or P815 target cells. T cell clones, derived by micromanipulation from microcultures selected for cytotoxic activity against YC8 and/or P815, maintained either the specific anti-allogeneic or the doubly reactive ( antiallogeneic plus anti-syngeneic tumor) phenotype. Fourteen clones (six specific and eight doubly reactive) were tested for cytotoxic activity on a panel of target cells with different haplotypes. All showed H-2-restricted specificity for minor histocompatibility antigens shared by DBA/2 and B10.D2. The restriction element for some of the clones mapped in the K region of the H-2 complex, whereas for other clones the restriction element mapped in the D region; both K- and D-restricted clones were able to lyse YC8. When the clones that exhibited lysis on YC8 were tested on two other BALB/c tumor targets, LSTRA, a Moloney virus induced lymphoma, and RL male-1, a radiation induced lymphoma, two of seven were found to lyse all three syngeneic tumor targets equally well, but not syngeneic BALB/c blasts. These clones were functionally categorized as conventional CTL because they were unable to proliferate when cultured with antigen in the absence of exogenous lymphokines, and were unable to produce lymphokine with IL 2 activity when stimulated by the appropriate splenocytes. When tested in vivo in a Winn assay, a strong anti-tumor activity against YC8 was exerted by the anti-DBA/2 clones DY4 -3 and DY16 -3. These clones lysed both YC8 and the immunizing target cells in vitro. No in vivo effect in neutralizing YC8 tumor growth was observed with clone D2-1, a clone that lysed DBA/2 targets but not YC8 in vitro.
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We have utilized a clonal approach to investigate functional and immunogenetic characteristics of T cells responsive to the miHA H-1.3. Our data prove the existence of H-2 I region-restricted helper T cells that are specific for H-1.3, or for determinants encoded by closely linked loci. These conclusions are based upon the following observations: 1) the cloned Th are driven to proliferate only by H-2 I-compatible stimulator cells that bear the appropriate (H-1.3) miHA; 2) antigenic stimulation causes the cloned Th to secrete lymphokine with high levels of IL 2-like activity; and 3) they are not specifically lytic for relevant target cells. These cloned Th were isolated at a rather low frequency from an H-1.3-immune MLC population compared with the observed frequency of H-1.3-specific Tc that proliferate autonomously after antigen stimulation; i.e., HITc isolated from the same MLC. They were, however, capable of promoting the clonal expansion of an H-1.3-specific HITc, suggesting that Th can collaborate with HITc in an anti-miHA response.
These studies present an efficient and sensitive method for detection of T cell growth factor (TCGF) activity in human lymphocyte cultures and illustrate that T cell growth factors are associated with T lymphocyte-mediated anti-HSV-1 responses. Secretion of TCGF is induced after stimulation of human peripheral blood mononuclear cells ( PBMNC ) with herpes simplex virus type 1 (HSV-1). Lymphokine activity is detected in a simple, sensitive method by studying [3H]thymidine incorporation after the addition of murine CTLL -20 cells to cultures of gamma-irradiated (4000 R), virus-stimulated PBMNC . By using this assay, we find that PBMNC from seropositive but not seronegative individuals produce detectable TCGF activity in a dose-dependent manner after incubation with HSV-1. Maximum activity is detected between 24 to 48 hr of incubation and correlates with in vitro proliferation of nonirradiated PBMNC in response to the virus. In addition, gamma-irradiated (1000 to 3000 R) PBMNC , which are frequently used as a source of antigen-presenting cells (APC), can secrete TCGF after contact with HSV-1. Lymphokine production by the APC-containing population is eliminated by gamma-irradiation (5000 R); such APC can still present UV-inactivated HSV-1 to HSV-1-responsive lymphoblasts, indicating that lymphokine production by T cells residing in the APC population is not essential for antigen presentation.