Linda L. Perry

Inflammation and Clearance of Chlamydia trachomatis in Enteric and Nonenteric Mucosae

ABSTRACT Immunization(s) fostering the induction of genital mucosa-targeted immune effectors is the goal of vaccines against sexually transmitted diseases. However, it is uncertain whether vaccine administration should be based on the current assumptions about the common mucosal immune system. We investigated the relationship between mucosal sites of infection, infection-induced inflammation, and immune-mediated bacterial clearance in mice using the epitheliotropic pathogenChlamydia trachomatis. Chlamydial infection of the conjunctival, pulmonary, or genital mucosae stimulated significant changes in tissue architecture with dramatic up-regulation of the vascular addressin, VCAM, a vigorous mixed-cell inflammatory response with an influx of α4β1+ T cells, and clearance of bacteria within 30 days. Conversely, intestinal mucosa infection was physiologically inapparent, with no change in expression of the local MAdCAM addressin, no VCAM induction, no histologically detectable inflammation, and no tissue pathology. Microbial clearance was complete within 60 days in the small intestine but bacterial titers remained at high levels for at least 8 months in the large intestine. These findings are compatible with the notion that VCAM plays a functional role in recruiting cells to inflammatory foci, and its absence from the intestinal mucosa contributes to immunologic homeostasis at that site. Also, expression of type 1 T cell-mediated immunity to intracellular Chlamydia may exhibit tissue-specific variation, with the rate and possibly the mechanism(s) of clearance differing between enteric and nonenteric mucosae. The implications of these data for the common mucosal immune system and the delivery of vaccines against mucosal pathogens are discussed.

Monoclonal antibodies to tissue-specific cell surface antigens: I. Characterization of an antibody to a prostate tissue antigen☆

Monoclonal antibodies were raised to PC-3 human prostate adenocarcinoma cells, and one hybridoma, designated F77-129, was extensively purified and used to characterize a PC-3 antigen. The F77-129 antibody also showed serological reactivity with the Du-145 prostate cancer line and with three of four breast carcinoma lines tested; it showed variable binding to a colon carcinoma line. Several other lines tested, including melanomas, fibrosarcomas, and leukemias, were completely negative. Immunoperoxidase staining of frozen surgical specimens showed binding to both normal and malignant prostate and breast tissue. Injection of radioiodinated F77-129 into tumor-bearing nude mice showed specific in vivo targeting to prostatic cancer implants. The antigen also showed surface modulation by bound antibody, suggesting possible clinical utility of this antibody in delivering immunotoxins to tumors.

Antigen presentation by epidermal Langerhans cells: loss of function following ultraviolet (UV) irradiation in vivo.

Abstract The antigen presenting capacity of cells derived from the skin of normal and ultraviolet (UV) light-irradiated mice has been investigated. Cells were obtained by a method developed in this laboratory that involves preliminary treatment of whole skin sections with trypsin followed by enzymatic digestion of skin fragments with collagenase. The resulting cell population is generally 80% viable and contains 5–8% I-A+ cells (Langerhans cells) by immunofluorescence using an FITC-conjugated monoclonal antibody. It was found that cells prepared in this manner, when haptenated with trinitrophenyl (TNP), induced significant delayed-type hypersensitivity (DTH) reactions in syngeneic recipients in numbers as low as 4 × 10 6 . Priming could be accomplished by subcutaneous and intraperitoneal but not intravenous administration of the coupled cells. This was evident in normal as well as in UV-treated recipients. In contrast, TNP-coupled cells obtained from UV-irradiated mice, while capable of inducing DTH responses in normal recipients, failed to induce DTH reactivity in UV-treated mice. Adoptive transfer of splenocytes obtained from the above groups of mice revealed the presence of suppressor cell activity in UV-treated mice given UV-derived epidermal cells. I-A+ cells are detectable in epidermal preparations from UV-treated mice but at quantitatively lower levels than in normal skin samples. The functional differences in antigen presentation and generation of suppressor cells by UV versus normal epidermal cells provides evidence for a severe defect in antigen handling by such cells in the UV-treated host.

Mechanisms of regulation of cell-mediated immunity: anti-I-A alloantisera interfere with induction and expression of T-cell-mediated immunity to cell-bound antigen in vivo.

The ability to modulate immunity to cell-bound antigen with anti-I-A alloantisera has been assessed. It was found that anti-I-A antiserum could inhibit the generation of T cell-dependent delayed-type hypersensitivity (DTH) responses to the S1509a tumor syngeneic to AJ mice and the chemical hapten, azobenzenearsonate, coupled onto the surface of syngeneic lymphoid cells. The intravenous injection of microliter amounts of anti-I-A alloantisera prevents the generation of immune T cells to either of the antigens employed. Kinetic analysis of the observed effect suggested that cellular interactions taking place at the time of antigen presentation during either immunization or challenge constituted the primary target of antiserum treatment. Finally, by using F1 hybrids, and immunizing these mice with antigen-coupled antigen-presenting cells of either parental types, it could be determined that anti-I-A antiserum was interacting primarily with cell surface structures involved in the presentation of nominal antigen to antigen-reactive cells. The general significance and potential application of these findings to therapeutic manipulations are also discussed.

Regulation of the immune response to tumor antigen: VIII. The effects of host specific anti-I-J antibodies on the immune response to tumors of different origin☆

Reduction of syngeneic tumor growth in primary tumor-bearing murine hosts has been accomplished using a variety of treatments designed to decrease endogenous suppressor cell activity or augment host effector responses. Selective interference with suppressor cell function can be achieved by in vivo administration of anti-thymocyte serums at critical times during the early stages of tumor development or by continuous treatment with antiserums directed to interact with I-J determinants on suppressor cells or suppressor factors. This later mode of therapy also results in a delay in tumor appearance when suboptimal doses of tumor are given. Preferential diminution of suppressor cell precursor activity has also been observed by pretreatment of tumor recipients with low doses of cyclophosphamide. Normal animals so treated are capable of adoptively transferring primarily helper-type activity to tumor-bearing recipients. Decreased tumor growth and prolonged host survival have also been achieved using BCG as a means of augmenting host effector potential. Thus, it is possible to inhibit tumor development in a murine model by modes of immunotherapy which may be relevant to the early treatment of certain human neoplasms.

Regulation of the immune response to antigens on the malignant cell surface

The ability of mammalian species to mount immune responses against structures present on the cell surface was discovered by Landsteiner [46] in studies of blood group antigens. The work of Gorer [20], clearly showed that tumor grafts would grow in syngeneic animals, but were rejected in allogeneic strains of mice; this then led to the study of the immunologic basis of graft rejection phenomena and eventually to successful organ transplantation [5]. It has been recently shown that primary tissue grafts from histoincompatible donors are consistently rejected by cellular immune responses of the recipient. The cells responsible for graft rejection belong to the L y t l + 2 subset of thymus-derived (T) cells [48]. The principal antigens which are recognized in the process of graft rejection are those encoded by genes in the major histocompatibility complex of the species [10], such as the H-2 locus in the mouse and the HLA locus in man.

Generation of a monoclonal antibody (Epenl) which binds selectively to murine ependymal cells

In order to define surface antigens unique to ependymal cells, spleen cells from C57/B16 mice immunized with a suspension of 70-80% purified isolated ependymal cells from syngeneic animals were fused with NS-1 myeloma cells. Five hybridomas were found which secrete monoclonal antibodies that recognize ependymal cells both by indirect immunofluorescence and radioimmunoassay. One of them, Epenl, appears to be a relatively specific surface marker of murine and rat ependymal cells, whereas the 4 others also recognize neurons, astrocytes, and/or oligodendrocytes. Absorption of Epenl with murine cerebral cortex did not affect its binding, whereas absorption with ependymal cells abolished it. Labeling of in vivo sections with Epenl demonstrates prominent binding to ependymal cells lining ventricular cavities. Epenl does not bind to neurons or astrocytes in culture, and binds only minimally to isolated oligodendrocytes. It does, however, recognize an antigenic determinant present in lung tissue.

The I-J subregion and surveillance.

A discussion of the control exerted by the I-J subregion of the H-2 complex over suppression, tolerance and self/non-self discrimination, and its implications in the study of tumour immunity and autoimmunity.

The role of anti-I-A antibody therapy in the management of autoimmune disease and in transplantation

Abstract Cellular immune responses are known to be influenced by gene products of the major histocompatibility complex (MHC). Cell surface antigens encoded by the I-A subregion of the MHC are critical in antigen processing and restricting CD4+ helper T-cell interactions. Antibodies directed against such antigens have been shown to modulate immune responses in vitro and in vivo. Anti-I-A antibody therapy has been shown to block antigen-specific T-cell activation, and to promote the development of antigen-specific T-suppressor cells. When applied to models of autoimmunity and allograft rejection in laboratory animals, anti-I-A antibody therapy has resulted in consistent and significant alterations in the natural history of these processes. Clinical application of this therapy to human disease has been inconsistent and disappointing. Before proceeding with further clinical trials, it will be important to standardize such antibodies with regard to isotype as well as antigen affinity and specificity.

Regulation of the immune response to tumor antigen. IV. Tumor antigen-specific suppressor factor(s) bear I-J determinants and induce suppressor T cells in vivo.

The nature and function of suppressor factor(s) elaborated by suppressor T cells in response to certain chemically induced tumors have been further defined. Thus, suppressor factor(s) specific for the S1509a methylchol-anthrene-induced fibrosarcoma have been shown to bear determinants encoded by the I-J subregion of the murine MHC since suppressive activity is removed by passage of the factor through an immunoadsorbent composed of anti-I-Jk coupled to Sepharose. No loss of activity was observed after passage of factor through control columns composed of normal mouse globulin. Furthermore, activity could be recovered from the relevant immunoadsorbent by elution with high salt. The administration of crude suppressor factor(s) to normal animals for 4 days resulted in the development of a population of suppressor cells that act in a manner analogous to the suppressor cell population used for production of factor. These factor-induced suppressor cells are T cells and exhibit an antigen specificity similar to that displayed by the tumor-induced suppressor cells. Thus, tumor-specific suppressor factor(s) bear I-J determinants and are capable of inducing the appearance of suppressor T cells in the nontumor-bearing host, which may then act in a specific manner to limit host responsiveness to tumor antigen.