Biomedical subjects
Publications and source records attributed to C P Sullivan.
Transplant team social workers are essential components of the team because of their knowledge and intervention skills in assisting patients. Sensitivity to the needs of the transplant patient is a catalyst for the development of creative intervention strategies.
An exploratory study to investigate perceived differences between searching full-text databases and bibliographic databases was undertaken. BRS's full-text database, Comprehensive Core Medical Library (CCML), and BRS's current MEDLINE file (MESH) were compared. Identical literature search topics were run in the two databases and the results evaluated regarding currency of search results, success in answering specific questions, uniqueness of information retrieved, and relevancy of retrieval. Additionally, connect time and costs were noted to aid in determining the feasibility of offering full-text database searching as a service for which the authors' institution would charge.
Major histocompatibility complex (MHC) restrictions in the secondary antibody response in vitro to the soluble protein antigen trinitrophenyl keyhole limpet haemocyanin (TNP-KLH) were investigated. Experimental conditions were employed which ensured that co-operation between KLH-primed T cells and TNP-primed B cells was possible only through linked recognition of carrier and haptenic determinants. Under such conditions co-operation between T and B cells appears to be MHC-restricted. These experiments were designed to distinguish between two possible reasons for such MHC restrictions: (i) interaction between T and B cells is directly restricted by the MHC; or (ii) MHC-restricted T cell-antigen-presenting cell (APC) interactions limit generation of antibody responses and thus impose a pseudo-MHC restriction on T-B interactions. The ability of F1 APC to circumvent MHC restrictions was determined. The capacity of KLH-primed T cells from (P X Q)F1 leads to parent P and parent P leads to F1 X-irradiation bone marrow chimaeras to help TNP-primed parent P and parent Q B cells was assayed. Such T cells preferentially co-operate with parent P B cells. Addition of F1 APC from the spleen and the peritoneum did not alter the MHC restriction. Antibody responses stimulated by either high or low antigen concentrations were similarly MHC-restricted. Stimulation with antigen-pulsed F1 APC also failed to circumvent MHC restrictions. These results suggest that in this system involving linked recognition of antigenic determinants, the MHC directly restricts interactions between T and B cells.
Mechanisms by which T and B lymphocytes co-operate in the in vitro secondary antibody response to trinitrophenyl (TNP)-conjugated soluble protein antigens were investigated. The generation of antibody responses was analyzed when haptenic and carrier determinants were either linked or non-linked. Ability to co-operate through each of these mechanisms was influenced by the experimental conditions employed, particularly the mode of preparation of the T cells and the antigen concentration used. Nylon wool filtration of T cells may deplete a T helper population involved in non-linked recognition interactions. High antigen concentrations favour the non-linked form of interaction whereas low antigen concentrations favour linked recognition interaction. These data suggest that at least two distinct co-operative mechanisms co-exist. However, experimental conditions can be defined under which either one mechanism predominates or where more than one mechanism is relevant.
Explore the source record for details and available documents.
Detailed analysis of the role of the structural characteristics of these molecules will require isolation of relatively large amounts of these antigens in serologically active form. We have purified murine Ia antigens on a large scale by affinity chromatography using monoclonal antibodies coupled to Sepharose 4B. Both I-Ak and I-Ek were isolated by sequential passage of cell lysate over columns prepared using specific monoclonal antibodies. Elution of the bound antigens required high pH (11-12) but, nonetheless, the purified material was 50-75% serologically active. Using LPS-stimulated spleen cells or B-lymphocyte tumor cells as starting material, 0.5 mg of each antigen can be readily purified. Based on antigen yields, it can be estimated that normal B-cells have about the same surface density of Class I and Class II MHC antigens. LPS blasts, in contrast, have normal levels of Class I antigen but 3-5 times higher levels of Class II antigens. We have now purified I-Ak and I-Ek from a number of different cell sources and have noted differences in both the mol. wts of the alpha- and beta-chains and in their apparent associations with cytoskeletal components. Proteins having the same apparent mol. wts as actin and myosin co-purify with both I-Ak and I-Ek antigens from various sources. These proteins do not co-purify with H-2K and D molecules obtained by similar methods, suggesting that Ia antigens may specifically interact with cytoskeletal elements.
Explore the source record for details and available documents.
The duration of the inductive effect of an antigen (alum-precipitated trinitrophenyl-keyhole limpet haemocyanin) was measured, in the presence and absence of responding spleen cells, by transfering a test population of spleen cells to irradiated mice at various times relative to antigen injection. Using allotype-congenic mice, the response of a test (Iga) population was estimated in the presence of responding (Igb) cells. In the absence of responding cells the inductive effect fell to 10% of the peak value in 9-10 days, but in their presence it reached this level in less than 5 days. Removal of T cells from the responding (Igb) population reduced their suppressive efficacy. It was concluded that B lymphocyte recruitment is curtailed not by the elimination of antigen but by an active suppressor mechanism involving suppressor T cells.