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J J Marchalonis

Publications and source records attributed to J J Marchalonis.

At least 19 recordsLinked to original sources
PubMed2005

Immunomodulation by immunopeptides and autoantibodies in aging, autoimmunity, and infection.

The operation of the immune system is a complex orchestration of specific self and non-self-recognition capacities mediated by cells of the innate system acting in coordination with T and B lymphocytes in a series of processes modulated by cytokines. We provide evidence for a natural immunomodulatory system involving autoantibodies directed against a controlling segment of T cell receptor Vbeta chains that downregulate production of stimulatory cytokines balanced by the peptides which in turn upregulate inflammatory activities mediated by TH1-type helper cells. TCR Vbeta-derived peptides effective in retrovirally induced immunosupression could also reverse the effects of immunosenescence in aged mice by restoring the balance of TH1- and TH2-type immunity and the resistance of the animals to cardiac pathology caused by infection with coxsackievirus. An unexpected finding was an adaptive role of the T cells from peptide-treated mice in remodeling damaged hearts by increasing net collagen synthesis by cardiac fibroblasts.

Aging↗
PubMed2003

Natural autoantibodies to TCR public idiotopes: potential roles in immunomodulation.

Autoantibodies directed against variable domain epitopes of the alpha/beta T cell receptor (TCR) occur in sera of man, mouse and other vertebrates. Here, we focus upon autoantibodies expressed in human rheumatoid arthritis (RA) and systemic erythematosus (SLE) with parallel studies involving collagen induced arthritis (CIA) in mice transgenic for human HLA-DR conferring resistance or susceptibility to autoimmune disease. We report specificity characterization of polyclonal and monoclonal IgM and IgG autoantibodies from SLE and for IgM monoclonal autoantibodies of RA patients. The data suggests that autoantibodies directed against "public" idiotopes present in the first complementarity determining region (CDR1) and the third framework (FR3) of the Vbeta gene products are generated in response to over-production of autodestructive T cells bearing particular Vbeta gene products and function to modulate (downregulate) the expression of these T cells. Since antibodies of these specificities are present in polyclonal IgG immunoglobulin (IVIG) preparations used for therapeutic purposes, the immunomodulatory effects of antibodies directed against TCR variable domains may account, at least in part, for the efficacy of IVIG preparations in therapy of autoimmune diseases and in the prevention of graft versus host reactions.

Animals↗
PubMed2001

Incorporation of long CDR3s into V domains: implications for the structural evolution of the antibody-combining site.

Available data suggest that 'primitive' antibody-combining sites often include longer than average HCDR3s. Long HCDR3 sequences have been reported in diverse vertebrates, including humans, cattle, camels and sharks. These long HCDR3 segments contain unusual sequence features such as stretches of Gly or Pro residues and multiple Cys residues. We examined how longer than average HCDR3s were accommodated in the V domains of human, murine and camel antibodies with known three-dimensional structures. The main conclusions were that (1) HCDR3s longer than 12 residues should protrude outward from the V domains; (2) descending HCDR3 polypeptides may utilize VL (including LCDR3) constituents as a platform, supporting the protruding segments; (3) intra- and inter-HCDR disulfides are frequently formed to rigidify the structure of HCDR3 or the combining site, and (4) V and C domains were possibly more similar in primordial antibodies than they are in their present day counterparts.

Amino Acid Sequence↗
PubMed2001

T-cell receptor-derived peptides in immunoregulation and therapy of retrovirally induced immunosuppression.

Retrovirally infected humans and mice showed progressive acquired immunodeficiency accompanied by the production of elevated levels of autoantibodies directed against T-cell receptor variable-domain epitopes. Epitope mapping analyses indicated that a major determinant recognized was defined by a 16-mer peptide containing the entire CDR1 segment and part of the FR2 region of human Vbeta8, and that both species showed reactivity to the same sequence. Either prophylactic or therapeutic administration of this peptide to retrovirus-infected C57/BL/6 mice normalized the balance of T(H)1- and T(H)2-type helper activity and restored the resistance to infection by the opportunistic parasite Cryptosporidium. Administration of the peptide did not generate significantly increased levels of autoantibody, but had a profound effect on T-cell activity as well as other aspects of inflammation, including NK-cell activity. A 16-mer derived from the Jbeta sequence showed similar functional effects on T cells from retrovirus-infected mice. Direct binding of the VbetaCDR1 peptide to recombinant TCR Valpha/Vbeta constructs, as well as to IgM natural autoantibodies, suggests that the cell surface receptor for the peptide is the alpha/beta TCR on T cells and surface IgM in B cells. The Vbeta CDR1 peptide stimulated division of murine splenocytes in vitro, stimulated the production of the T(H)1 cytokine IL-2, and synergized with the T-cell mitogen concanavalin A in proliferation and IL-2 production. These studies indicate that administration of peptides derived from T-cell receptor variable domains to animals immunosuppressed as a result of retroviral infection has a profound immunomodulatory effect enhancing overall T-cell functional capacity, particularly with respect to the cytokine production characteristic of T(H)1-type cells. Our studies are interpreted in the context of other recent investigations of immunomodulatory peptides.

Amino Acid Sequence↗
PubMed2000

Production and characterization of monoclonal IgM autoantibodies specific for the T-cell receptor.

Natural autoantibodies to the T-cell receptor (Tcr) have been identified in all human sera. However, titer, epitope specificity, and isotype vary with physiological conditions, autoimmune diseases, and retroviral infections. The levels of anti-Tcr autoantibodies in rheumatoid arthritis (RA) patients are significantly higher than in normal individuals, and the autoantibodies are typically IgM. To obtain detailed information on these autoantibodies, we generated B-cell heterohybridomas secreting monoclonal IgM autoantibodies (mAAbs) from the synovial tissue and peripheral blood of RA patients. We selected clones secreting mAAbs that bound a major Vbeta epitope defined by a synthetic peptide that contains the CDR1 region of the Vbeta 8.1 gene product. From these we isolated a subset of seven mAAbs that bound a recombinant single-chain Valpha/Vbeta construct containing the peptide epitope and, also to JURKAT cells which express Vbeta 8.1. The mAAbs produced by these clones were distinct from each other in their V-region sequences. However, all the V regions were essentially identical to germline sequences in both the heavy and light chains. Heavy-chain CDR3 segments ranged in length from 17 to 26 residues, did not correspond to any known autoantibodies, and showed extensive N-region diversity in the V(D)J junctions. Five monoclonal autoantibodies use VH 3 genes, while the remaining two utilized VH 4 sequences. Light-chain variable regions used were Vkappa3 (two), Vlambda3 (four), and one Vlambda2. These autoantibodies derived their unique features from their CDR3 segments that could not be aligned with any known sequences.

Amino Acid Sequence↗
PubMed2000

TCR v(beta) usage and clonality of T cells isolated from progressing and rejected tumor sites before and after in vitro culture.

A gelatin sponge model of concomitant tumor immunity was employed in order to examine the clonality of T cells associated with progressing and rejected tumor sites. Here we show that freshly isolated T cells bearing TCR V(beta)1, CDR3 RPGTGN, J(beta)1.1 and TCR V(beta)8, CDR3 GD, J(beta)1.6 predominated progressing and rejected tumor sites. Despite the similarity in T cell populations, the T cells from rejected tumor sites were capable of killing the autologous tumor cells, whereas T cells from progressing tumor sites were not able to do so. The differing cytolytic ability could not be attributed to a difference in TCR zeta chain protein expression levels between both T cell populations. After a 5 day mixed lymphocyte tumor culture the T cells from the progressing tumor site were capable of killing autologous tumor cells, which suggested changes took place within the cell population during in vitro culture. Further TCR analysis revealed T cells bearing TCR V(beta)1, CDR3 RPGTGN, J(beta)1.1 and TCR V(beta)8, CDR3 GD, J(beta)1.6 were not expanded following the in vitro culture. These data suggest that the lack of cytotoxicity of freshly isolated tumor-infiltrating lymphocytes (TIL) was not due to abnormal TCR zeta chain expression or major differences in the TCR V(beta) usage. Additionally, the gain of TIL effector function did not correlate with an expansion of the TCR bearing T cells found to predominate the in vivo response. These data suggest that the predominant TCR V(beta) used by lymphocytes infiltrating regressing or rejected tumors may not represent the tumor reactive T cells that grow in culture or respond to the autologous tumor in vitro.

Animals↗
PubMed1999

Construction and binding analysis of recombinant single-chain TCR derived from tumor-infiltrating lymphocytes and a cytotoxic T lymphocyte clone directed against MAGE-1.

The TCR is responsible for the specificity of cytotoxic T lymphocytes (CTL) by recognizing peptides presented in the context of MHC. By producing recombinant soluble TCR, it is possible to study this interaction at the molecular level. We generated single-chain TCR (scTCR) from tumor infiltrating lymphocytes (TIL) and one CTL clone directed against melanoma-associated antigen (MAGE)-1. Sixty-eight day anti-MAGE-1 TIL and one cloned anti-MAGE-1 CTL were analyzed by PCR for their Valpha and Vbeta gene usage. The TIL population showed a restriction in Valpha and Vbeta usage with only Valpha4 and Valpha9 and Vbeta2 and Vbeta7 expressed. The anti-MAGE-1 CTL clone demonstrated absolute restriction with only Valpha12 and Vbeta1 expressed. DNA sequence analysis was performed on all V regions. For the TIL, each possible Valpha-Vbeta combination (i.e. Valpha4-Vbeta2, Valpha9-Vbeta2, Valpha4-Vbeta7 and Valpha9-Vbeta7) was constructed as a distinct scTCR and the recombinant proteins expressed in bacteria. From the anti-MAGE-1 TIL, Valpha4-Vbeta2 scTCR demonstrated binding activity to HLA-A1(+) cells pulsed with MAGE-1 peptide. Results obtained from screening a panel of our scTCR constructs on HLA-A1(+) cells pulsed with MAGE-1 peptide or irrelevant peptide demonstrated that Vbeta2 plays a significant role in binding to the MAGE-1 peptide. Amino acid alignment analysis showed that each Vbeta sequence is distinctly different from the others. These findings demonstrate that soluble TCR in single-chain format have binding activity. Furthermore, the results indicate that in TCR, like antibodies, one chain may contribute a dominant portion of the binding activity.

Amino Acid Sequence↗
PubMed1998

A stochastic model for the rapid emergence of specific vertebrate immunity incorporating horizontal transfer of systems enabling duplication and combinational diversification.

Recent molecular data indicate that the antigen-specific combinatorial immune response is restricted to jawed vertebrates where it is found in representatives of all class from cartilagenous fishes to mammals. Here, we analyse the relatively rapid emergence of the combinatorial system terms of three stochastic process, with the system reaching essentially full capacity in immunoglobulin recognition elements and diversification and recombination of gene segments in an evolutionary span of time of less than 20 million years. The mechanisms for inducibility were coopted from ancient and widely spread processes in phylogeny for regulation of cell division. The proposed process of formation entailed the evolution of unknown ancestral genes into those specifying bona fide immunoglobulin domains, and the generation of multiple copies of these via a series of events facilitated by horizontal transfer of site-specific recombinases and recombination signal sequences most probably from microbial and fungal sources. The second process is one of rapid "decay" (evolution) which occurred in about 10 million year under stringent selective conditions to generate proper conserved canonical sequences. The third process is that of the long term evolution of these characteristic immunoglobulin domains over the 450 million years since their emergence. As a first approximation the rates of these three processes were computed using first order differential equations. The rate of formation has a magnitude of 10-7 substitutions per site per year, and that of rapid modifications is 10-8 substitutions per site per year. The long term rate of immunoglobulin evolution is comparable to that of other moderately conserved proteins, (1-3) x 10-9 substitutions per site per year). This model is testable by searching for "footprints" of microbial and fungal DNA processing enzymes and recombination mechanisms. The hypothesis raises the general concept that horizontal transfer of genes facilitating rearrangement and duplication can catalyse major steps of macroevolution.

Animals↗
PubMed1998

Injection of T-cell receptor peptide reduces immunosenescence in aged C57BL/6 mice.

Previous studies established that retrovirally infected young mice produced large amounts of autoantibodies to certain T-cell receptor (TCR) peptides whose administration diminished retrovirus-induced immune abnormalities. C57BL/6 young (4 weeks) and old (16 months) female mice were injected with these same synthetic human TCR V beta 8.1 or 5.2 peptides. Administration of these autoantigenic peptides to old mice prevent immunosenescence, such as age-related reduction in splenocyte proliferation and interleukin-2 (IL-2) secretion. TCR V beta peptide injection into young mice had no effect on T- or B-cell mitogenesis and IL-4 production while modifying tumour necrosis factor-alpha (TNF-alpha), IL-6, and interferon-gamma (IFN-gamma) secreted by mitogen-stimulated spleen cells. TCR V beta injection also retarded the excessive production of IL-4, IL-6 and TNF-alpha induced by ageing. These data suggest that immune dysfunction and abnormal cytokine production, induced by the ageing process, were largely prevented by injection of selected TCR V beta CDR1 peptides.

Aging↗
PubMed1998

Antibodies of sharks: revolution and evolution.

The combinatorial immune response is restricted to jawed vertebrates with cartilaginous fishes being the lowest extant species to have the mechanism for diversification and an extensive panoply of immunoglobulins, T-cell receptors and MHC products. Here, we review the molecular events of the "big bang" or rapid evolutionary appearance of the functionally complete combinatorial immune system coincident with the appearance of ancestral jawed vertebrates, suggesting that this event was catalyzed by horizontal transfer of DNA processing systems. We analyze the nature and extent of variable and constant domain diversity among the distinct immunoglobulin sets of carcharhine sharks focusing upon the lambda-like light chains and the mu and omega heavy chains. The detection and isolation of natural antibodies from the blood of unimmunized sharks illustrates a surprising range of recognition specificities and the existence of polyspecificity suggests that the antibody-forming system of sharks offers unique opportunities for studies of immunological regulation. Although the homologies between shark and mammalian immunoglobulins are unequivocal, major differences in segmental gene organization present challenges to our understanding of basic immunological phenomena such as clonal restriction.

Amino Acid Sequence↗
PubMed1997

Analysis of autoantibodies to T-cell receptors among HIV-infected individuals: epitope analysis and time course.

Individuals seropositive for human immunodeficiency virus type 1 (HIV) express elevated levels of autoantibodies (AAbs) directed against recombinant T-cell receptors (TCRs) and synthetic peptide epitopes duplicating beta chain markers. We performed longitudinal studies of anti-TCR AAbs in HIV-1-infected individuals, making comparisons with uninfected sera and sera from other individuals infected with a nonviral agent. We determined levels of autoantibodies by titration using enzyme-linked immunosorbent assay (ELISA) and developed a means for characterizing "autoantibody CDR recognition spectrotypes" for individual sera. Antibody levels against certain defined synthetic epitopes were substantially elevated in HIV-infected subjects relative to reactivities by control groups. Individual sera showed relatively high AAb levels to a subset of CDR1 peptide epitopes. Two patients who subsequently developed AIDS showed particular reactivity to Vbeta2.1, 8.1, 10.1, and 22.1 epitopes. Our results show that production AAbs to TCR Vbeta epitopes is a general consequence of HIV infection. The response is individual but shows some restriction and shifts in AAb subpopulations often occur with time.

Adult↗
PubMed1997

Molecular origins and evolution of immunoglobulin heavy-chain genes of jawed vertebrates.

Cartilaginous fish are the most ancient extant jawed vertebrates possessing bona fide immunoglobulin (Ig) and T-cell receptor molecules. The study of these animals is critical for understanding the origins of the vertebrate immune system. Here, Samuel Schluter, Ralph Bernstein and John Marchalonis review the latest data concerning heavy-chain variable genes and associated isotypes in these animals, and propose a model for the early origins of Igs.

Animals↗
PubMed1997

Physical and epitope analysis of a recombinant human T-cell receptor V alpha/V beta construct support the similarity to immunoglobulin.

The genetic organization and protein structure of T-cell receptors (TCR) and immunoglobulins (Ig) are remarkably similar. Through recombinant, physical, and peptide-based immunological studies we demonstrated that rabbit antisera generated against a recombinant single-chain TCR (scTCR) react with defined peptide epitopes of their constituent TCR alpha and beta chains. These antisera cross-react with the lambda light-chain Mcg as well as with peptides duplicating its covalent structure. Conversely, rabbit antisera generated to human lambda light chains cross-reacted with the recombinant scTCR. Rabbit anti-lambda antibodies purified on an scTCR affinity column bound to T-cell lines and to T and B lymphocytes from peripheral blood. Circular dichroism analysis demonstrated plots characteristic of beta-sheets for both Mcg and recombinant scTCR. Antisera directed against TCR alpha-chain synthetic peptides reacted with scTCR, Mcg lambda light-chain protein, synthetic peptides from regions of sequence homology in beta-chains, and Mcg. Based upon this homology and the serological cross-reactions which reflect conformational determinants, we suggest that the V alpha/V beta antigen-binding domain of this particular monoclonal scTCR construct is substantially similar to the conformational structure of lambda light chains.

Amino Acid Sequence↗