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T C Fuller

Publications and source records attributed to T C Fuller.

At least 19 recordsLinked to original sources
PubMed1991

Monitoring HLA alloimmunization. Analysis of HLA alloantibodies in the serum of prospective transplant recipients.

The identification of serum HLA alloantibody in clinical transplantation can only be considered meaningful if the information derived from clinical tests can be used to predict crossmatch outcome. Drawing on the foundations and principles of blood transfusion medicine, this article presents a strategy for efficient, cost-effective patient HLA antibody monitoring that relies on a screening technique identical in sensitivity to the final donor crossmatch method. Application of this approach to the successful transplantation of highly immunized patients using HLA disparate cadaver renal allografts supports the contentions advanced within this article.

Epitopes↗
PubMed1990

Topographic map of the HLA-A2 CREG epitopes using human alloantibody probes.

The topographic architecture of the epitopes expressed on the HLA-A2 glycoprotein using murine monoclonal antibody (mAb) probes indicates at least two sterically distinct domains. Previously, we have demonstrated using human HLA alloantibodies (aAb) that multiple determinants are expressed on each HLA antigen: the highly polymorphic private epitopes and the public determinants that are shared within a family of crossreactive groups (CREG). Our objectives now focus on probing the antigenic structure of the HLA-A2-28-9-B17 CREG using highly specific aAb in conjunction with mAb that have previously been used for structural studies. Both mAb-mediated blockage of complement-dependent cytotoxic aAb and reciprocal antibody (Ab) binding inhibition assays with quantitation by fluorescence flow cytometry have been utilized. We have found that xenogeneic mAb directed against A2-69, A2-B17, and A2-28 crossblock aAb of the same serologic specificity, and vice versa, indicating that the epitopes they respectively recognize are at least in close steric proximity. However, additional HLA-A2, A28, and B17 aAb of private specificity and A2-28-9 aAb of public specificity, for which there are no known mAb counterparts, paint an additional complexity not previously known. We conclude that at least four different alloepitopes can be expressed by each serologically defined HLA antigen. Based on the primary sequence data, we have assigned the location and the amino acid substitutions which most likely account for these discrete epitopes. The unique private determinants are located on the alpha 1 domain together with the interlocus A2-B17 epitope while the public epitopes A2-69, A2-28-9 and A2-28 are located on the alpha 2 domain.

Antibodies, Monoclonal↗
PubMed1990

Epitope map of the HLA-B7 CREG using affinity-purified human alloantibody probes.

Monoclonal antibodies (mAb) recognizing the B7 CREG have been used to construct an epitopic map of HLA-B7. Similar studies with human HLA alloantisera have been lacking due to the polyclonal nature of the alloantibodies (aAb). Detergent-solubilized HLA Class I antigens were purified and coupled to activated CH-Sepharose 4B. Sequential affinity isolation of aAb populations using a series of HLA antigen columns enabled us to produce a battery of aAb eluates against both the private B7, B13, B27, and B omega 60 determinants and the public B7-42, B7-60, B7-60-61, B7-27-13-60, B7-42-22-27, B7-8-42-60-41, and B omega 6 epitopes. The topographic relationship of the B7 family of determinants recognized by the Ab probes was derived using crosscompetition Ab blocking assays with quantitation by indirect immunofluorescence and FACS analysis. We have found that aAb and mAb of similar specificity crossblock; Ab of different specificity give complex patterns including both overlapping blocking between the alpha domains and Ab-induced conformational change of the molecule. From these investigations, we conclude that HLA Class I alloantigens bear both multiple, topographically distinct public epitopes and separate private determinants that can be distinguished using human aAb probes. At least four discrete epitopes are expressed by each molecule of the HLA-B7 CREG and can be ascribed to unique aa substitutions on the hydrophilic beta loops of the distal heavy chain domains and also on several exposed areas of the alpha helices. These findings are extremely similar to those of the HLA-A2 CREG and suggest that possibly all Class I molecules possess a comparable, complex degree of serologic polymorphism.

Antibodies, Monoclonal↗
PubMed1990

1,000 renal transplants at the Massachusetts General Hospital: improved allograft survival for high-risk patients without regard to HLA matching.

Excellent allograft survival is now routinely accomplished following renal transplantation. Changes in immunosuppression have resulted in a significant improvement in early survival for recipients of primary LRD and CD allografts. In our series, crossmatching techniques which accurately assess alloantibody reactivity and not the degree of HLA mismatch have also permitted successful transplantation of such high-risk groups as recipients of second transplants and highly sensitized recipients. However, a yearly attrition rate of allograft loss persists for all recipients. These long-term observations stress the need for newer approaches to immunosuppression in the future, which include protocols that allow for an indefinite tolerance to incompatible donor antigens.

Adult↗
PubMed1989

Variation in patient response associated with different preparations of murine monoclonal antibody therapy.

The sera of 37 renal and 12 liver allograft recipients treated with OKT3 (42), Leu2a (7), or both (2) monoclonal antibodies were serially analyzed by an enzyme-linked immunosorbent assay to determine the humoral response (IgG) to mAb. Anti-mAb IgG to the treatment mAb was detected in the serum of 23 (76%) renal and 6 (50%) liver OKT3 recipients, and all 7 Leu2a renal recipients, usually within 14 days of mAb completion, but never during the first week of Rx. Each of the 7 Leu2a recipients developed reactivity not only to Leu2a isotype (IgG1), but also to OKT3 isotype (IgG2a). In contrast, only 1 of the 42 renal and liver allograft recipients treated with OKT3 developed reactivity to the Leu2a isotype. Blocking studies indicated that the specificity of the response to the treatment mAb was directed at the idiotype--and, in some patients, to the constant domain (isotype) of the mAb administered. The antibody response to an alternate isotype (IgG2a) observed in Leu2a (IgG1)-treated patients most likely resulted from irrelevant immunoglobulin (IgG2a) in the Leu2a preparation. This reactivity appeared to be specific for the IgG2a subclass. Clinicians administering mAb therapy should be aware that various mAb preparations may contain immunoglobulin isotypes unrelated to the therapeutic mAb. Crossimmunization to the irrelevant immunoglobulins may occur, precluding subsequent use of other mAbs sharing similar isotype.

Antibodies, Anti-Idiotypic↗
PubMed1989

Function and surface phenotype of T lymphocytes infiltrating renal allografts in nonhuman primates treated with monoclonal antibodies.

The phenotype and function of T lymphocyte cell lines established in vitro from kidney biopsies at the time of acute cellular rejection were studied using a nonhuman primate renal allograft model. Our objectives were to investigate the function and surface phenotype of cells that infiltrate renal allografts in animals that were untreated, that were given subtherapeutic cyclosporin, or that developed rejection after treatment with monoclonal antibodies to IL-2R B chain (CD25), immune cell adhesion molecule-1 (ICAM-1), or CD8. Lines from allograft biopsies and peripheral blood were expanded in vitro using solely human recombinant IL-2 and analyzed after 6-20 days in culture. We found that the large majority of cells cultured from cynomolgus allografts at the time of acute rejection or, when possible, assayed directly without culture, were CD3+4-8+ T lymphoblasts that possessed donor-specific cytolytic function and an NK-line, cytotoxic activity. In contrast, it was rarely possible to establish T cell lines exhibiting donor-specific cytotoxic activity from the blood except in the absence of immunosuppression or during CsA taper. A stable number of graft-derived CD4+8- cells was only observed in an unsuppressed animal 2 days after transplantation in the absence of manifest signs of rejection. Taken together, the above data indicate that similar T lymphocyte populations associated with allograft rejection are present in acutely rejecting allografts after the various types of immunosuppressive therapy. Since the infiltrating cells were similar to those obtained prior to therapy, recurrent rejection most likely represents cells that have escaped elimination. The T cells derived from monkey grafts differ from those from human renal allografts by the decreased frequency of CD4+ cells. Whether this difference is species-related or therapy-related is not known.

Animals↗
PubMed1989

A critical analysis of serum and urine interleukin-2 receptor assays in renal allograft recipients.

A component of the interleukin 2 receptor (IL-2R) is released in soluble form during T cell activation and can be detected in the blood during acute renal allograft rejection. This study evaluates the diagnostic utility of a sandwich enzyme immunoassay test for serum and urine IL-2R in renal allograft recipients. A rise in serum IL-2R during the week prior to the clinical diagnosis of rejection correlated better with rejection than did isolated serum IL-2R levels or urine values. For the diagnosis of acute rejection, a rise in serum IL-2R (sensitivity 73%, specificity 87%) was comparable in overall test performance to a rise in serum creatinine (sensitivity 70%, specificity 84%). Overall, the two tests had equivalent receiver operating characteristic curves. Because the etiology of false positives in creatinine and IL-2R assays differed (primarily cyclosporine toxicity and infection, respectively), the predictive value of the combined tests was superior to either alone.

Creatinine↗
PubMed1988

HIV-1 reverse transcriptase is a target for cytotoxic T lymphocytes in infected individuals.

Characterization of the host immune response to human immunodeficiency virus type 1 (HIV-1) is critical to the rational design of an effective AIDS vaccine. In this study, cytotoxic T lymphocytes (CTL) specific for HIV-1 reverse transcriptase (RNA-dependent DNA polymerase) were found in blood samples from HIV-1-infected individuals. CTL targets were prepared by immortalizing B cells from ten seropositive and six seronegative individuals, and then infecting these cells with recombinant vaccinia viruses containing HIV-1 genes. CTL directed against autologous B lymphoblasts expressing HIV-1 reverse transcriptase were detected in fresh blood samples from eight HIV-1 seropositive subjects, but in no seronegative controls. The effector cells were identified as major histocompatibility complex-restricted CD3+CD8+ lymphocytes. Because the HIV-1 pol gene is highly conserved among different isolates and generates both humoral and cellular immune responses, it bears consideration for inclusion in a candidate AIDS vaccine.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Plasma interleukin 2 receptor levels in renal allograft recipients.

Shed/soluble interleukin 2 receptor (IL2R) was measured by an enzyme-linked immunosorbent assay (ELISA) in serial samples of plasma from 32 patients with renal allografts. Patients on chronic dialysis (pretransplant) had elevated IL2R levels which fell toward normal after transplantation. Patients with acute rejection and viral infection had significantly higher levels of plasma IL2R than did patients with stable renal function or with cyclosporine nephrotoxicity (all P less than 0.005). Acute renal failure from other causes (renal artery stenosis, hemolytic-uremic syndrome) did not have a comparable rise in IL2R. The assay of shed/soluble IL2R may have diagnostic value in the clinical management of allograft recipients, a possibility that deserves further clinical evaluation.

Antibodies, Monoclonal↗
PubMed1987

Public epitopes and the antigenic structure of the HLA molecules.

Simplified procedures for determining amino acid sequences in proteins and nucleotide sequences in DNA have rapidly expanded the number of MHC molecules for which primary amino acid structure is known. These molecules will be especially valuable as tools to study the structure-function relationships of globular proteins because of the extensive polymorphism of genes coding the MHC genes products. The general three-dimensional structure of class I MHC molecules was recently deduced, but the more subtle topographical microconformations are still undefined. Definition and topographical mapping of epitopes, defined by serological or cellular immune effector products, will be critical probes for these three-dimensional studies. Comparative studies of amino acid sequences among various MHC and molecules have revealed distinct regions of hypervariability in the alpha-1 and -2 domains of class I heavy chains and the alpha-1 and beta-1 domains of most class II molecules. Mutant MHC molecules that differ from each other by no more than one to three amino acids can have structural changes which may result in a loss of the private epitopes that defined the allelic gene product. On the basis of these studies, the private epitopes are thought to be determined by one or more of the hypervariable regions. Similar studies of the relationships between specific regions of the molecule and public epitopes are not fully explored. Because public epitopes are partially conserved structures, one might expect that their structure is not principally determined by hypervariable region. In fact, however, some public epitopes, such as A2/B17 and BW4/Bw6, do map to diversity regions. Epitope mapping as a means of identifying specific topographic sites and relating these sites to specific functional regions of the molecule will be difficult unless the epitopes themselves are better defined. Thus, the capacity to distinguish spatially distinct public epitopes from cross-reactive homologous private epitopes will be important if epitope-specific immunological probes are use to map specific regions of an MHC molecule. Many investigators are interested in the possibility that some components of HLA alloimmunization are regulated through idiotypic networks. Suciu-Foca and colleagues have provided preliminary evidence that epitope-specific HLA alloantibodies bear dominant idiotypic determinants. Antibodies to these determinants appear during pregnancy, following blood tranfusion, and following renal allograft transplantation, also, the antibodies have been correlated with renal allograft survival.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies, Monoclonal↗
PubMed1986

Monoclonal antibody therapy. Anti-idiotypic and non-anti-idiotypic antibodies to OKT3 arising despite intense immunosuppression.

The frequency, timing, and specificity of the humoral antibody response to a murine monoclonal antibody (OKT3, IgG2a) were measured in 21 consecutive renal allograft recipients. These patients received i.v. OKT3, 1-5 mg/day for 10-20 days as treatment for acute graft rejection. Maintenance immunosuppression consisted of azathioprine and corticosteroids. Using three different assays, an antibody response was detected in 75% of the 20 patients with adequate samples. The ELISA assay of the overall IgM and IgG reactivity to OKT3 revealed that IgM anti-OKT3 appeared in 65% and IgG anti-OKT3 in 50% of the patients, reaching a peak 20-33 days after the last dose of OKT3. The IgM preceeded the IgG in most cases (P less than 0.02) and in 8 cases was detected during therapy. One patient had high levels of IgM anti-OKT3 before therapy, yet responded normally to OKT3. Interference with the therapeutic effectiveness was evident in one patient who developed IgG antibodies during therapy. His serum blocked the binding of F-OKT3 to normal lymphocytes in the presence of normal BALB/c serum. The blocking assay, done by flow cytometry, measured anti-idiotypic (Id) reactivity since the sera did not affect the binding of OKT8 (another IgG2a) or anti-Leu4 (another anti-T3), and the blocking activity remained after affinity absorption with normal mouse IgG. Using this assay, 60% of the patients made an anti-Id response. One made only anti-Id, and several had anti-Id at times when other reactivities were undetectable. Antibodies to non-idiotypic, presumably isotypic, determinants represented on OKT8 occurred in only 44%, while other reactivity (OKT4; IgG2bK) was less common (12%) and weaker. While no adverse allergic reactions occurred in this group of patients, the anti-Id antibodies, which are a prominent feature of the immune response to this and probably other monoclonal antibodies, can block their therapeutic effectiveness and can arise despite intense immunosuppression. This response may require the use of different idiotypes for prolonged or repeated courses of therapy and may be the major obstacle to the use of human monoclonal antibodies.

Antibodies, Anti-Idiotypic↗
PubMed1985

A minor subset of HLA-DR3 haplotypes is preferentially increased in type 1 (insulin-dependent) diabetes.

We have been using human T-lymphocyte clones specifically sensitized to detect leucocyte antigens of Type 1 (insulin-dependent) diabetic patients in the hope of detecting novel HLA antigens associated with Type 1 diabetes. We previously described two such clones which define a new class II HLA antigen, Boston-1 (BO1). BO1 is found mainly on cells of persons with particular HLA-DR antigens and, of potential significance for diabetes, BO1 identifies a distinctive subset of DR3 haplotypes. We report here that BO1+ DR3 haplotypes are overrepresented in Type 1 diabetes. That is, significantly more of the DR3-positive subjects are BO1-positive in the patient group (31%) than in the control group (8%), suggesting that a diabetes-susceptibility gene may be more common on the BO1+ than on the BO1- DR3 haplotypes. Alternative interpretations are also discussed.

Alleles↗
PubMed1985

Characterization of in vivo-activated allospecific T lymphocytes propagated from human renal allograft biopsies undergoing rejection.

To evaluate in situ lymphocyte responses in cell-mediated immune tissue injury, we have developed an approach for propagation of human allospecific T lymphocytes directly from tissue biopsies. We have utilized renal allograft tissue obtained from eight patients undergoing cellular rejection. Needle biopsy tissue was cultured in medium containing interleukin 2 (IL 2), including recombinant-DNA-produced IL 2. In each case, lymphoblasts migrated out of the tissue and increased in numbers, especially adjacent to the tissue. In two cases in which there was no cellular infiltrate present in the biopsy, no lymphocytes proliferated in vitro. Instead, fibroblasts eventually filled the wells from these allograft biopsies. The continued presence of the allograft tissue enhanced the viability and growth of the lymphoblasts in cultures from rejecting allografts. The isolated lymphoblasts had surface markers of mature OKT3+ lymphocytes of either OKT4+ or OKT8+ subsets. OKT8+ cells predominated. There was variability (41 to 97%) in the percentage of T lymphoblasts that bore surface HLA-DR antigens. In assays of lymphoblasts obtained from eight separate renal allografts, there was donor-specific cytotoxicity, and in all but two of the cases there was donor-induced proliferation. The specificity of the cytotoxic reaction was tested by using 51Cr-labeled, PHA-stimulated target cells prepared from a panel of HLA-typed donors. Proliferation was tested after 48 hr in the presence of mitomycin C-treated peripheral blood mononuclear cells as stimulator cells by using only 10(4) responder T lymphoblasts. Of particular note was that the cytotoxicity of the isolated lymphoblasts showed specificity against both "private" HLA class I alloantigens (of the allograft donor) as well as "public" cross-reacting epitopes. This method permits the propagation and functional characterization of in vivo-activated T lymphoblasts that are obtained from the actual sites of immune-mediated injury. Preliminary studies of other tissues with diverse inflammatory processes indicate the possible widespread applicability of obtaining in vivo-activated lymphocytes.

Antigens, Surface↗
PubMed1984

Antigenic polymorphism of the T4 differentiation antigen expressed on human T helper/inducer lymphocytes.

The human TH lymphocyte population has been established to express a differentiation antigen (T4) which appears to function in cellular collaboration and T cell recognition of Class II MHC alloantigens. Because we observed altered immunofluorescence staining of the TH cells of some individuals using the OKT4 mAb, a systematic investigation on both the epitopic structure of the T4 glycoprotein molecule and possible polymorphism of these epitopes was undertaken. From competitive blocking assays using eight murine anti-T4 mAbs coupled with quantitative flow cytometry, at least five and possibly seven different epitopes can be recognized on the T4 molecule. Population studies showed some individuals had a reduced phenotypic expression of the OKT4 reactive determinant to one-half that of normal and others completely lacked this epitope. The OKT4 reactive epitope variations are common but have so far been racially restricted to American Blacks and do not appear related to the stage of TH cell differentiation, any identifiable immune abnormality in vitro, or a definable disease process. The OKT4 epitope cannot be unmasked by neuraminidase treatment or T cell stimulation with lectins, soluble antigens, or allogeneic lymphocytes. Coupled with a family study, the alterations in OKT4 phenotype are best explained by autosomal, codominant expression of the T4 gene product. The significance of this polymorphism on TH cell function remains unclear.

Antibodies, Monoclonal↗
PubMed1983

Direct estimation of the frequency of human cytotoxic T lymphocytes and their precursors following in vitro allosensitization.

Cell mediated lympholysis (CML) has been proposed as an in vitro model of the rejection process that results from transplantation of allogeneic tissue. To date, the absolute frequencies of cytotoxic T lymphocytes (CTL) and their precursors (CTL.P) have not been directly estimated in man because of technical difficulties. Through optimizing the conditions for radiometric detection of 51Cr release and the attendant improvement in CML sensitivity, direct CTL frequency estimates have been determined in peripheral blood (PBL), spleen (SPL), and lymph nodes (LNC) after in vitro allostimulation using unrelated human cells and limiting dilution assays. The mean frequency of CTL generated from PBL is 1 in 826 cells (0.121% +/- 0.101%) which, from preliminary experiments, is significantly greater than that generated from either LNC or SPL (p less than 0.05). With restimulation of primed cells on day 10, the frequency of CTL generated from PBL was increased 400%. The CTL.P frequency (0.0064% +/- 0.0050%) was approximately 5% of the corresponding CTL frequency. The CTL.P frequencies were found to be minimal estimates as both accessory "filler" cells and T cell growth factors increased the level of detection of CTL.P an average of threefold. The limiting cell dilution assay as detailed in this report should be a powerful tool for defining the cellular requirements and related factors necessary for optimal induction of a CTL response and should provide the means for determination of the immunogenetic requirements and the allospecificity of human cytotoxic lymphocytes.

Cells, Cultured↗