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Biomedical subjects

A La Cava

Publications and source records attributed to A La Cava.

12 recordsLinked to original sources
PubMed2001

H-2D end confers dominant protection from IL-10-mediated acceleration of autoimmune diabetes in the nonobese diabetic mouse.

BALB/c mice that express IL-10 as a transgene in their pancreatic beta cells (Ins-IL-10 mice) do not develop diabetes, even after crossing to nonobese diabetic (NOD) mice ((Ins-IL-10 x NOD)F(1) mice). However, backcross of F(1) mice to NOD mice (NOD.Ins-IL-10 mice) results in N2 and N3 generations that develop accelerated diabetes. In this study, we found that NOD.Ins-IL-10 mice that expressed BALB/c-derived MHC molecules (NOD.Ins-IL-10(H-2(g7/d)) mice) were protected from diabetes. This protection associated with peri-islet infiltration and preserved beta cell function. Moreover, expression of I-A(d) and I-E(d) MHC class II molecules of BALB/c origin was not responsible for protection, but NOD.Ins-IL-10 mice that expressed BALB/c MHC class I D(d) molecules (NOD.Ins-IL-10(H-2(g7/d)) mice) did not develop diabetes. To directly test the possibility of a protective role of H-2D(d) in the development of accelerated diabetes, we generated transgenic mice expressing D(d) under the control of the MHC class I promoter. We found that double transgenic NOD.Ins-IL-10-D(d) mice developed accelerated diabetes in a fashion similar to NOD.Ins-IL-10 mice that were D(d) negative. Microsatellite analysis of H-2D(d)-linked loci confirmed association between BALB/c-derived alleles and protection of NOD.Ins-IL-10(H-2(g7/d)) mice. These results suggest a control of H-2D(d)-linked gene(s) on IL-10-mediated acceleration of autoimmune diabetes and dominant protection of the D(d) region in NOD.Ins-IL-10 mice.

Animals↗
PubMed2000

A mechanism for IL-10-mediated diabetes in the nonobese diabetic (NOD) mouse: ICAM-1 deficiency blocks accelerated diabetes.

Neonatal islet-specific expression of IL-10 in nonobese diabetic (NOD) mice accelerates the onset of diabetes, whereas systemic treatment of young NOD mice with IL-10 prevents diabetes. The mechanism for acceleration of diabetes in IL-10-NOD mice is not known. Here we show, by adoptive transfers, that prediabetic or diabetic NOD splenocytes upon encountering IL-10 in the pancreatic islets readily promoted diabetes. This outcome suggests that the compartment of exposure, not the timing, confers proinflammatory effects on this molecule. Moreover, injection of IL-10-deficient NOD splenocytes into transgenic IL-10-NOD.scid/scid mice elicited accelerated disease, demonstrating that pancreatic IL-10 but not endogenous IL-10 is sufficient for the acceleration of diabetes. Immunohistochemical analysis revealed hyperexpression of ICAM-1 on the vascular endothelium of IL-10-NOD mice. The finding suggests that IL-10 may promote diabetes via an ICAM-1-dependent pathway. We found that introduction of ICAM-1 deficiency into IL-10-NOD mice as well as into NOD mice prevented accelerated insulitis and diabetes. Failure to develop insulitis and diabetes was preceded by the absence of GAD65-specific T cell responses. The data suggest that ICAM-1 plays a role in the formation of the "immunological synapse", thereby affecting the generation and/or expansion of islet-specific T cells. In addition, ICAM-1 also played a role in the effector phase of autoimmune diabetes because adoptive transfer of diabetogenic BDC2.5 T cells failed to elicit clinical disease in ICAM-1-deficient IL-10-NOD and NOD mice. These findings provide evidence that pancreatic IL-10 is sufficient to drive pathogenic autoimmune responses and accelerates diabetes via an ICAM-1-dependent pathway.

Adoptive Transfer↗
PubMed2000

Cell-mediated DNA transport between distant inflammatory sites following intradermal DNA immunization in the presence of adjuvant.

After intradermal genetic immunization, naked DNA is transported from the site of injection to regional lymph nodes. Little is known on how inflammation influences this process and whether DNA is transported beyond local lymph nodes. In the experiments herein reported, we injected naked DNA in the presence of adjuvant to address questions related to 1) the fate of naked DNA in the presence of inflammation; 2) the generation of immune responses to the encoded protein during inflammation; and, more in general, 3) the fate of ingested molecules beyond regional lymph nodes during inflammation. Two sites of inflammation were induced in vivo in mice. Naked DNA was injected in the nape together with adjuvant, and adjuvant only was injected at a distant peritoneal site. Injected DNA, uptaken at the primary dermal site of inflammation, was transported beyond regional lymph nodes to distant organs such as the spleen and to the distant peritoneal site of inflammation. This transport, mediated by CD11b+ cells, was cumulative during chronic inflammation. These results indicate a novel route of transport of DNA beyond regional lymph nodes and may have specific implications for DNA-based immune modulation.

Adjuvants, Immunologic↗
PubMed2000

Genetic immunization for the recovery and purification of recombinant proteins.

A system that uses genetic immunization for recombinant protein recovery and purification is described. The genetic sequence encoding a target protein is subcloned into both a eukaryotic and a prokaryotic vector. With the eukaryotic construct, a rabbit is genetically immunized and specific polyclonal antibodies to the encoded protein raised. The prokaryotic construct is used for bacterial transformation and expression of recombinant protein. Recovery and purification of target recombinant protein are obtained by passing the lysate of expressing bacteria through an immunoaffinity column prepared with the polyclonal antibodies raised in the genetically immunized animal. This method allows purification of recombinant protein without fusion tails and can be applied to purify any protein whose encoding genetic sequence is known.

Animals↗
PubMed2000

Pancreatic expression of interferon-gamma protects mice from lethal coxsackievirus B3 infection and subsequent myocarditis.

Cardiovascular disease is one of the leading causes of death worldwide, and has been associated with many environmental risk factors. Recent evidence has indicated the involvement of pathogens such as viruses as causative agents, and specifically identified the coxsackievirus B serogroup as the leading culprit. Not only has coxsackievirus B3 (CB3) been identified from patients with cardiovascular disease, but also infection of mice with CB3 strains can reproduce human clinical heart disease in rodents. Several mechanisms have been proposed in an attempt to distinguish between pathology mediated by direct viral destruction of cardiac muscle cells or by the virus-induced immune response directed at infected myocytes or at 'mimicked' epitopes shared between viral and cardiac antigens. To distinguish between these mechanisms, we infected a unique mouse that diminishes the extent of infection and spread of the virus, but allows complete immunity to the virus. Transgenic mice expressing interferon-gamma in their pancreatic beta cells failed to develop CB-3-induced myocarditis. This work challenges the idea of the function of the immune response and 'molecular mimicry' in the CB-3-induced autoimmune myocarditis model, and instead favors the idea of virus-mediated damage. These results emphasize the benefit of reducing the level of viremia early during infection, thereby reducing the incidence of virus-mediated heart damage and autoimmunity.

Animals↗
PubMed1999

Ontogeny of synonymous T cell populations with specificity for a self MHC epitope mimicked by a bacterial homologoue: an antigen-specific T cell analysis in a non-transgenic system.

By means of a novel technique for identification and isolation of MHC class II-restricted antigen-specific T cells, we describe here in non-transgenic BALB / c mice physiological positive selection of an oligoclonal population of T cells which recognizes both a self MHC-derived peptide (Ialpha52) and a bacterial homologoue (Hi15). The results support a model for self peptide-mediated generation of T cells which have specificity for microbial antigens through molecular mimicry. This mechanism may be a model for the ontogeny of a physiological T cell response to infectious agents. Loss of control of these circuits may be part of the inciting factors of autoimmunity.

Animals↗
PubMed1997

Genetic bias in immune responses to a cassette shared by different microorganisms in patients with rheumatoid arthritis.

Rheumatoid arthritis (RA) is an autoimmune disease associated with HLA-DRbeta1 alleles which contain the QKRAA amino acid sequence in their third hypervariable region(s). The QKRAA sequence is also expressed by several human pathogens. We have shown previously that an Escherichia coli peptide encompassing QKRAA is a target of immune responses in RA patients. Here we address two questions: first, whether QKRAA may function as an "immunological cassette" with similar, RA-associated, immunogenic properties when expressed by other common human pathogens; and second, what is the influence of genetic background in the generation of these responses. We find that early RA patients have enhanced humoral and cellular immune responses to Epstein-Barr virus and Brucella ovis and Lactobacillus lactis antigens which contain the QKRAA sequence. These results suggest that the QKRAA sequence is an antigenic epitope on several different microbial proteins, and that RA patients recognize the immunological cassette on different backgrounds. ANOVA of immune responses to "shared epitope" antigens in monozygotic twin couples shows that, despite significantly elevated responses in affected individuals, a similarity between pairs is retained, thus suggesting a role played either by hereditary or shared environmental factors in the genesis or maintenance of these responses.

Antigen Presentation↗
PubMed1997

B-cell superantigens: molecular and cellular implications.

B cell superantigens are proteins that are capable of immunoglobulin variable region mediated binding interactions with the naive B cell repertoire at frequencies that are orders of magnitude greater than occur for conventional antigens. Within this review we discuss recent observations regarding the molecular basis of these interactions and the distribution of superantigen binding capacities in different human B cell populations. These findings and current predictions regarding the relevance of these proteins to the physiologic development of immune repertoires are also discussed.

Aging↗
PubMed1995

Positive selection in autoimmunity: abnormal immune responses to a bacterial dnaJ antigenic determinant in patients with early rheumatoid arthritis.

A novel 'multistep molecular mimicry' mechanism for induction of rheumatoid arthritis (RA) by bacterial antigens that activate T lymphocytes previously 'educated' by peptides derived from a class of human histocompatibility antigens is reported here. These antigens have the amino acid sequence QKRAA, which is also present on the Escherichia coli heat-shock protein dnaJ. Synovial fluid cells of early RA patients have strong immune responses to the bacterial antigen, but cells from normal subjects or controls with other autoimmune diseases do not. The activated T cells may cross-react with autologous dnaJ heat-shock proteins that are expressed at synovial sites of inflammation. Our findings may have direct relevance to new strategies for the immune therapy of RA.

Amino Acid Sequence↗
PubMed1994

A novel strategy of c-myc oncogene in NK activity regulation not related to the W6/32 MHC class-I epitope.

The c-myc gene encodes a nuclear protein whose precise function is still not fully understood. Introduction of a c-myc gene into a number of cell lines leads to an increase in their susceptibility to NK-cell lysis. It was reported earlier that c-myc can induce a decrease in the membrane expression of the MHC class-I molecules and this may be one of the factors that render target cells relatively more susceptible to NK lysis. In this contribution, we show, in a human LCL line transfected with a constitutively active c-myc gene, an increased sensitivity to NK lysis, which correlates with an augmented effector-target binding ability of c-myc-transfected LCLs and with a high ICAM-I expression rather than with down-regulation of MHC class-I W6/32 epitope expression.

Animals↗
PubMed1991

NK and LAK susceptibility varies inversely with target cell MHC class I antigen expression in a rat epithelial tumour system.

Several cell clones derived from cell lines obtained from a rat thyroid carcinoma, induced by in vivo injection of the Kirsten murine sarcoma virus into thyroid gland, and from its spontaneous lung metastases were analysed for their major histocompatibility complex (MHC) class I antigen expression. The susceptibility to natural killer (NK) cell lysis of these clones, differing in their levels of MHC class I antigen expression, was determined and found to vary inversely with the target cell MHC level, confirming numerous reports of the literature. We then tried to localize the step of the multistage natural cytotoxic process, in which class I antigens could interfere, and tested first whether lymphokine (IL-2) activation of the killer (LAK) cells could overcome the differences in MHC class I expression of target cells. As this did not appear to be the case, we studied the binding step by either a cold target inhibition assay and a target binding assay and found that target cells expressing class I antigens show a lower competitive capacity for effector cells than targets not expressing such antigens, indicating that this interference may occur, at least in our system, in the binding step of the cytotoxic process.

Animals↗