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J J Marchalonis

Publications and source records attributed to J J Marchalonis.

At least 37 records · Page 2Linked to original sources
PubMed1997

Retrovirally induced mouse anti-TCR monoclonals can synergize the in vitro proliferative T cell response to bacterial superantigens.

Antibodies directed against the beta chain of the T-cell receptor (TCR) have been detected in animals and in humans in a number of distinct immune states that do not involve direct immunization with either T cells or TCR epitopes. When C57B1/6 mice are infected experimentally with the LP-BM5 retrovirus mixture they produce increased titres of autoantibodies directed against TCR V beta complementarity determining region 1 (CDR1) epitopes. Here, the authors utilized hybridoma technology to isolate monoclonal immunoglobulin (Ig)M antibodies (MoAbs) that arose at the peak of infection. The authors characterized the binding specificity tested using synthetic peptides modelling the CDR1 segments of 24 distinct V beta gene products and determined the VH gene usage by two such monoclonals. One binds to a restricted set of TCR V beta CDR1 peptides, and the second reacts with approximately half of the CDR1 peptide homologues. These MoAbs are specific for T-cell receptor beta chains and do not bind to immunoglobulin light chains or to unrelated protein molecules. Both MoAbs bind to intact T cells expressing the V beta domain (human V beta 8 and mouse V beta 11) from which selection peptides were derived, and costimulate a V beta specific in vitro T cell proliferative response induced by the staphylcoccal enterotoxin E (SEE) superantigen.

Amino Acid Sequence↗
PubMed1997

The T-cell receptor as immunoglobulin: paradigm regained.

The quest to determine the molecular nature of T-lymphocyte receptors for antigen was a "holy grail" to immunologists for over 25 years. This paper updates a review written 15 years ago (Marchalonis JJ, Hunt JC. Proc Soc Exp Biol Med 171:127-145, 1982), which proposed that "these molecules apparently do not bear determinants specified by the major histocompatibility complex, but express Ig-related variable regions and constant regions unique to T-cell products." We review subsequent contributions from molecular biology, protein chemistry, peptide immunochemistry, and structural biology establishing that T-cell receptors (TCRs) are members of the immunoglobulin family restricted to T cells that share 3-dimensional structural features, sequence homology, antigenic cross-reactivity, and common mechanisms of diversification with conventional immunoglobulins. These molecules and their light- and heavy-chain siblings appeared contemporaneously in vertebrate evolution with the emergence of sharks. We illustrate how extrapolation of concepts from immunoglobulin to T-cell receptors has aided in the understanding of these often enigmatic molecules, and, conversely, how concepts derived for T-cell receptors such as the role of "superantigens" can be directly applied to conventional immunoglobulins. A second precept that follows from the symmetry of the combining sites of Igs and TCRs is that MHC-restricted antibodies should exist. Such molecules have in fact been reported, and the x-ray crystallography for T-cell receptors suggests that the combining sites recognizing simultaneously MHC and peptide epitopes resemble the combining sites of antibodies directed against protein determinants. Additional immunoglobulin molecules of nonmammalian species have been detected and characterized based upon conserved homology to TCR and Igs, and it is anticipated that further study will enable the identification of more antigen-specific members of the family in mammals as well.

Amino Acid Sequence↗
PubMed1997

Binding of human IgG myeloma proteins to autologous T-cell receptor determinants.

IgG myeloma proteins (MPs) produced by monoclonal plasma cells derived from B2 lymphocytes have been reported to bind to various autoantigens but the binding generally has been of low affinity. Moreover, T cells from some multiple myeloma patients can respond specifically to idiotypes of their own paraproteins. We analyzed the capacity of more than 20 human IgG MP to bind, a recombinant single-chain molecule containing complete V beta 8.1 and V alpha 1 structures, sets of synthetic peptide epitopes corresponding to a complete TCR beta chain, and a set of CDR1 epitopes corresponding to 24 human V beta gene products, and intact monoclonal T cells. Two of 20 MPs bound strongly to the recombinant TCR. Five of the same set, including these, bound to a synthetic epitope corresponding to the CDR1 segment. On a mass basis, the binding was approximately 1000-fold greater than that of pooled polyclonal IgG. The binding activity was confined to the Fab fragment and was specifically inhibitable by appropriate peptide determinants. Spectrotypic analysis using a set of CDR1 epitopes indicated that individual proteins showed characteristic binding patterns ranging from highly specific to relatively promiscuous. Highly reactive MPs also bound to TCR on intact cells in immunocytofluorescence by flow cytometry. These results are consistent with the relatively frequent occurrence of autoantibodies to TCR determinants and indicate that MPs can be derived from this autoantibody subset.

Amino Acid Sequence↗
PubMed1996

Primordial emergence of the recombination activating gene 1 (RAG1): sequence of the complete shark gene indicates homology to microbial integrases.

The rearrangement of antibody and T-cell receptor gene segments is indispensable to the vertebrate immune response. All extant jawed vertebrates can rearrange these gene segments. This ability is conferred by the recombination activating genes I and II (RAG I and RAG II). To elucidate their origin and function, the cDNA encoding RAG I from a member of the most ancient class of extant gnathostomes, the Carcharhine sharks, was characterized. Homology domains identified within shark RAG I prompted sequence comparison analyses that suggested similarity of the RAG I and II genes, respectively, to the integrase family genes and integration host factor genes of the bacterial site-specific recombination system. Thus, the apparent explosive evolution (or "big bang") of the ancestral immune system may have been initiated by a transfer of microbial site-specific recombinases.

Amino Acid Sequence↗
PubMed1996

Effects of vaccination against different T cell receptors on maintenance of immune function during murine retrovirus infection.

Murine retrovirus infection causes an aberrant stimulation of several subsets of T helper 2 cells identified by their T cell receptors (TCR). C57BL/6 mice were treated with synthetic peptides based upon different human TCR V beta CDR1 sequences following experimental infection with the murine retrovirus. Previous studies established that retrovirally infected mice produced autoantibodies to certain of these peptides, and their administration after infection diminished many of the cytokine abnormalities induced by the virus. This study determined whether the complete 16-mer synthetic peptides modeling the V beta CDR1/FR3 were required, and whether admixture of autoantigenic peptides synergized immune preservation. Treatment with complete TCR pep beta 3 and pep V beta 5.2 peptide alone and combined largely prevented the retrovirus-induced reduction in B and T cell proliferation and Th1 cytokine secretion while suppressing excessive production of Th2 cytokines, which are stimulated by retrovirus infection. Treatment with overlapping short peptides corresponding to the N-terminal 11-mer and C-terminal 12-mer did not significantly prevent the immune dysfunction in retrovirus-infected mice. These data suggest that immune dysfunction and abnormal cytokine production, induced by murine retrovirus infection, were largely prevented by TCR V beta CDR1 peptides, and the complete CDR1 in association with the five residues from FR2 was required.

Amino Acid Sequence↗
PubMed1996

A new high molecular weight immunoglobulin class from the carcharhine shark: implications for the properties of the primordial immunoglobulin.

All immunoglobulins and T-cell receptors throughout phylogeny share regions of highly conserved amino acid sequence. To identify possible primitive immunoglobulins and immunoglobulin-like molecules, we utilized 3' RACE (rapid amplification of cDNA ends) and a highly conserved constant region consensus amino acid sequence to isolate a new immunoglobulin class from the sandbar shark Carcharhinus plumbeus. The immunoglobulin, termed IgW, in its secreted form consists of 782 amino acids and is expressed in both the thymus and the spleen. The molecule overall most closely resembles mu chains of the skate and human and a new putative antigen binding molecule isolated from the nurse shark (NAR). The full-length IgW chain has a variable region resembling human and shark heavy-chain (VH) sequences and a novel joining segment containing the WGXGT motif characteristic of H chains. However, unlike any other H-chain-type molecule, it contains six constant (C) domains. The first C domain contains the cysteine residue characteristic of C mu1 that would allow dimerization with a light (L) chain. The fourth and sixth domains also contain comparable cysteines that would enable dimerization with other H chains or homodimerization. Comparison of the sequences of IgW V and C domains shows homology greater than that found in comparisons among VH and C mu or VL, or CL thereby suggesting that IgW may retain features of the primordial immunoglobulin in evolution.

Amino Acid Sequence↗
PubMed1996

Heavy-chain variable regions in carcharhine sharks: development of a comprehensive model for the evolution of VH domains among the gnathanstomes.

We determined the sequence of 18 DNA clones encoding VH regions of sandbar shark and bull shark. All of these sequences exhibit key structural coding features characteristic of known VH genes of higher vertebrates. These VH sequences disclosed considerable diversity, and can be divided into six families according to the criterion of 80% DNA sequence identity. The overlapping of some VH gene clones to two or more families is a particular feature found in carcharhine sharks, which suggests that VH diversification is a continuing process. The basic sequence patterns of heavy-chain V regions found in all representative gnathanstomes and in VH of the shark heavy immunoglobulin IgW provides evidence for selection of canonical residues in all VH structures. Elasmobranch VH sequences can be divided into two classes or clans, one comprising the 'classical' VH set and the other comprising VHS related to those of IgW (V omega). Phylogenetic analyses place the VH cluster as the root of all the classic VHS and indicates that the V omega set is most probably that of the primordial heavy chain.

Amino Acid Sequence↗
PubMed1996

T-cell-receptor dose and the time of treatment during murine retrovirus infection for maintenance of immune function.

C57BL/6 mice were injected with different doses of human T-cell receptor (TCR) V beta 8.1 CDR1 peptide at different times after murine retrovirus (LP-BM5) infection. Injection with TCR V beta 8.1 CDR1 peptide largely prevented the retrovirus-induced reduction in B- and T-cell proliferation, and T-helper 1 (Th1) cytokines [interleukin-2 (IL-2) and interferon-gamma (IFN-gamma)] secretion. It also suppressed T-helper 2 (Th2) cytokines (IL-6 and IL-10) production, which was stimulated by retrovirus infection. These effects were accomplished using at least 100 micrograms of peptide per mouse and the most effective dose of peptide had to be given within 4 weeks after retrovirus infection. Immunization with doses above 100 micrograms/mouse as long as 4 weeks postinfection maintained natural killer (NK) cell activity during retrovirus infection. Reducing the dose of peptide or delaying it until the disease progressed towards early murine acquired immune deficiency syndrome (AIDS) allowed development of immune dysfunction. These studies provide data suggesting that immune dysfunction, induced by murine retrovirus infection, was largely prevented by TCR V beta CDR1 peptide injection.

Adjuvants, Immunologic↗
PubMed1996

Peptide epitope binding specificity and V K and V H gene usage in a monoclonal IgM natural autoantibody to T cell receptor CDR1 from a viable motheaten mouse.

Autoantibodies (AAbs) to T cell receptor (TCR) determinants are produced in humans during the course of rheumatoid arthritis and systemic lupus erythematosus as well as in retroviral infections. We have examined the binding specificity of a panel of monoclonal antibodies derived from mutant viable motheaten (mev) mice against several TCR peptide determinants representing the complementary determining region 1 (CDR1) regions of various Vbeta families, and have identified one mAb, UN37-5, that shows high affinity binding with specificity for two CDR1 peptide determinants. The light and heavy chain V genes of UN37-5 were sequenced and compared to known V genes. The UN37-5 V H gene sequence represents the V H J6O6 family and is most similar to a previously reported V H gene derived from a germ line DNA fragment representing a unique J606 family V H gene. This germ line V H gene is also used by previously characterized mev derived mAbs directed against thymocyte and RBC antigens. The UN37-5 V L gene sequence represents the V K 4/5 gene family. It has 87% homology with the V K Ox-1 germline gene. The UN37-5 V K sequence has greater than 95% identity at the amino acid level with VK L chains from IgM hybridomas specific for DNA and the influenza virus hemagglutinin. The specificity of this AAb is determined by the V H CDR3 and a V K chain which has not been utilized in previously reported mev autoantibodies.

Amino Acid Sequence↗
PubMed1996

Autoantibodies to T-cell receptor beta chains in human heart transplantation: epitope and spectrotype analyses and kinetics of response.

Autoantibodies against T-cell receptors have been found in two alloimmunization situations in humans: renal transplantation and pregnancy. We carried out longitudinal studies of human heart transplant recipients monitoring their autoantibody production to a recombinant single chain T-cell receptor V alpha/V beta construct, a set of nested, overlapping peptides duplicating the complete covalent structure of an individual T-cell receptor beta chain and a set of peptides duplicating the first complementarity determining segments of 24 distinct human V beta gene products in order to define the time course, epitope specificity and recognition heterogeneity of the response. Autoantibodies against intact and peptide-defined V beta and C beta determinants were generated following human heart allotransplantation. The responses generally show an increase following transplantation that subsequently decreases with time, a result which is consistent with a single immunization. However, some patients showed elevated responses as long as 12 months following the transplant. Autoantibody anti-CDR1 spectrotype analyses detected individual differences among patients, but 5 of 8 patients characterized in detail showed elevated IgG binding to CDR1 peptide epitopes of V beta 6.1, 21.1 and 22.1 gene products. Autoantibodies to CDR1 epitopes of V beta 7.1 and 8.1 were high pretransplant and remained high, although the relative increases with respect to the pretransplant values were not as impressive as those for the above CDR1 epitopes and others usually present in low quantity, e.g. anti-V beta 2.1, 3.1 and 24.1. Although there was great disparity between the MHC haplotypes of donors and recipients, and individual differences among patients, the degree of restriction in the autoantibody response was surprising and suggests a common step in recognition and regulation of the response to allografts.

Amino Acid Sequence↗
PubMed1995

Diversity of Ig light chain clusters in the sandbar shark (Carcharhinus plumbeus).

The genes encoding Ig chains in elasmobranchs are arranged in clusters or cassettes, an organizational pattern dramatically different from the mammalian translocon gene arrangement. Cluster gene arrangements, which have now been found in non-elasmobranchs as well, pose interesting dilemmas for understanding the mechanisms of Ig gene expression and regulation in terms of allelic exclusion and clonal selection. We have sequenced five lambda genomic clones encoding complete sandbar shark (Carcharhinus plumbeus) lambda L chain gene loci. While the coding regions among all five clones are highly homologous, the noncoding regions have significant differences that allowed us to identify two types of lambda L chain clusters. The noncoding regions are < 60% identical between groups, while the three clones belonging to the first group share > 95% identity in their noncoding regions. The second group is more diverse and may be comprised of several related subgroups. The two clones in this group share approximately 85% identity in the noncoding regions. Variations in the promoter region, including octamer and TATA box orientation and position, are identified between the two groups and may have implications for the molecular regulation of Ab production. Our results show the sandbar shark lambda L chain family to be a complex and diverse system.

Amino Acid Sequence↗
PubMed1995

T cell receptor V beta complementarity-determining region 1 peptide administration moderates immune dysfunction and cytokine dysregulation induced by murine retrovirus infection.

Murine AIDS, induced by LP-BM5 murine leukemia retrovirus infection, causes a progressive and profound immunodeficiency in female C57B1/6 mice. Previously, we reported that autoantibodies were elevated during the initiation phases of this murine retrovirus infection and bound peptide determinants corresponding to CDR1 of several TCR V beta-chains. Therefore, we designed studies to determine whether administration of a major autoimmunogenic TCR V beta CDR1 peptide before or after infection with LP-BM5 retrovirus would modulate retrovirus-induced dysregulation of T cell function. Administration of the TCR V beta CDR1 peptide before murine retrovirus infection significantly prevented its suppression of splenic NK cell activity, T and B cell proliferation, and monokine (IL-6 and TNF-alpha) and Th1 cytokine (IL-2 and IFN-gamma) release by splenocytes, and inhibited retrovirus-induced elevation of Th2 cytokine (IL-5 and IL-10). Similar data were obtained with peptide immunization 2 wk after murine retrovirus infection at 6 and 16 wk postinfection. However, delaying peptide immunization until severe suppression of T and B cell mitogenesis had occurred did not restore their functions. Immunization with TCR V beta peptide prevents development of retrovirus-induced immune dysfunction, which suggests a possible pathogenic role of autoreactive T cells as regulatory elements.

Amino Acid Sequence↗
PubMed1995

T lymphocytes infiltrating sites of tumor rejection and progression display identical V beta usage but different cytotoxic activities.

Most tumors grow progressively and overwhelm the host. The rare but documented cases of spontaneous regression of primary tumors are indicative of the potential of tumor-bearing hosts to develop a significant antitumor response. Because most tumors grow progressively in the host, it is not surprising that the majority of studies have focused on T lymphocytes that infiltrate these tumors. Although these studies have generated significant and useful information during the period of tumor growth, they can only speculate on the mechanisms that are involved in tumor rejection. We have used a well developed sponge model of concomitant tumor immunity that allows us to compare the immunologic events that occur during tumor progression vs rejection. In this model, an animal harboring a primary EMT6 mammary tumor is challenged with a secondary tumor implant through a pre-implanted gelatin sponge. During the manifestation of concomitant tumor immunity, the secondary tumor is rejected and the effector cells mediating the response are retained within the sponge matrix. Using this model we analyzed the TCR usage, cytotoxic activity of lymphocytes, and cytokine production at both tumor sites. The data revealed that tumor-rejecting lymphocytes isolated from the site of secondary tumor implant were cytotoxic toward EMT6 cells, whereas tumor-infiltrating lymphocytes isolated from the progressing primary tumor were not. Interestingly, the TCR-V beta repertoire of the tumor-infiltrating lymphocytes and tumor-rejecting lymphocytes were identical with V beta 1 and V beta 8 being predominant at both sites. Furthermore, the rejection site showed higher gene expression of IFN-gamma, TNF-alpha, and IL-10 whereas TGF-beta expression was slightly higher in the progressing tumors. These findings suggest that the disparate effector functions observed during tumor progression vs rejection are not caused by different T cell phenotypes but may be due instead to influences exerted by cytokines produced at the tumor sites.

Animals↗
PubMed1995

Autoantibodies against peptide-defined epitopes of T-cell receptors in retrovirally infected humans and mice.

Autoantibodies directed against peptide-defined epitopes of T-cell receptors occur in the serum of healthy humans with the levels and isotypic expression dependent upon physiological changes (aging, pregnancy) or upon the development of autoimmune disease. We carried out investigations of autoantibodies against Tcr peptide-defined epitopes in retroviral infections of humans (HIV-1) and mice (LP-BM5 strain of murine leukemia virus) to determine whether infection with these agents disrupted the regulation of the production of these antibodies. Retroviral infection in humans resulted in increased levels of autoantibody production against putative immunoregulatory regions of the Tcr beta chain (V beta CDR1 and Fr3), a result reflecting a disruption of regulation. In addition, antigenic mimicry was observed with a cross-reaction shared between the common portion of the V3 neutralizing loop of the HIV-1 gp120 molecule and the joining segment of T-cell receptors (J beta). Infection of mice with the defective retrovirus resulted in the induction of antibodies directed particularly against V beta CDR1 peptide-defined determinants. Analysis of the virally induced response to a set of 8 CDR1 peptide epitopes indicated a selectivity to the process. It was possible to partially reverse aberrant cytokine changes correlated with the onset of murine MAIDS by administration of T-cell receptor peptides in saline. These results show that retroviral infection in humans and mice has a profound dysfunctional effect on the regulation of autoantibodies to T-cell receptors. The function of these autoantibodies in the immunopathogenesis of acquired immunodeficiency remains to be determined.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Characterization of autoantibodies directed against T cell receptors.

Recently it has been observed that administration of intravenous immunoglobulin (IVIG) can have profound effects on a wide variety of diseases related to the dysregulation of the immune system. The mechanisms which explain these activities are poorly understood. Human IVIG and various Cohn plasma fractions contain autoantibodies directed against T cell receptors (Tcr). Previous studies have shown that IVIG contains autoantibodies against T cell receptor peptides. In order to further our understanding of autoantibody specificities, a single chain Tcr (scTcr) was constructed by recombinant DNA techniques from the variable alpha and variable beta chains of the Jurkat cell line. Anti-Tcr autoantibodies were isolated from IVIG and Cohn fractions I + III using a scTcr affinity column. This scTcr affinity purified material reacted with the surfaces of T cells at 10 micrograms/ml whereas non-purified IVIG did not. Sera from patients with rheumatoid arthritis (RA) as well as serum from patients with systemic lupus erythematosus (SLE) reacted with the scTcr at levels above that of normals.

Animals↗
PubMed1995

Autoregulation of Tcr V region epitopes in autoimmune disease.

Normal individuals possess low levels of autoantibodies specific for certain peptide defined regions of T-cell receptor (Tcr) variable regions, particularly CDR1 and Fr3. These regions are predicted to be exposed on the surface of the native molecule and, by analogy and comparison with immunoglobulins, correspond to public idiotype determinants. The anti-Tcr idiotype antibodies appear to be ubiquitous and we propose that they play a role in the regulation of T-cell function. To delineate the parameters of expression of these antibodies, we characterized anti-Tcr antibody activity in normal individuals, in those suffering from the autoimmune diseases rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), and in patients with non-autoimmune arthritis (osteoarthritis) as a disease control. There were significant increases in autoantibody levels in the autoimmune patients. There was also variation in isotype and the particular variable regions recognized. IgM autoantibodies directed against a few peptide defined determinants were elevated in RA, whereas SLE patient sera showed high levels of IgG binding to a broad spectrum of Tcr peptides.

Arthritis, Rheumatoid↗
PubMed1995

Production of IgG autoantibodies to TCRs in mice infected with the retrovirus LP-BM5.

Autoantibodies (AAbs) directed against particular segments of the variable region of TCR beta chains occur in normal humans and in certain autoimmune diseases, but the factors regulating the appearance of such antibodies are unknown. We report that AAbs binding a peptide determinant corresponding to the CDR1 of the V beta domain are elevated in C57BL/6 mice following infection with the LP-BM5 murine leukemia retrovirus mixture, a treatment used to induce murine AIDS. The elevation of the level of these AAbs is an early event following retroviral infection which corresponds in part to the general polyclonal activation of the B cells, but a selectivity for particular V beta sequences is apparent later. This suggests that the appearance of these antibodies may play a part in the subsequent development of immunodeficiency. Since the antibodies studied are of the IgG isotype, both T cells and B cells are involved in their elaboration.

Amino Acid Sequence↗