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Biomedical subjects

T M Setcavage

Publications and source records attributed to T M Setcavage.

12 recordsLinked to original sources
PubMed1993

Column agglutination technology: the antiglobulin test.

A new system for typing and screening blood, based on the sieving effect of glass bead microparticles, has been developed. The test is performed in a microcolumn in which the red cell agglutinates are trapped in the glass bead matrix during centrifugation, and unagglutinated cells form a pellet at the bottom of the column. Anti-human globulin reagents were incorporated in the diluent and the new test system, column agglutination technology, was compared to conventional tube tests and low-ionic-strength method. Sera and plasmas (228 samples) were screened for red cell antibodies with two anti-human globulin reagents: one containing only anti-IgG and the other containing both anti-IgG and anti-C3b, -C3d. After initial testing, there was 94-percent agreement between column agglutination technology and tube tests, and after repeat testing, there was 97-percent agreement. The column agglutination technology anti-human globulin test eliminates the need to wash red cells, which decreases the overall test time. The test is easy to perform, and the results are more objective than those with tube and microplate methods.

Antibodies, Anti-Idiotypic↗
PubMed1981

Immune response to immobilized sheep erythrocyte monolayer.

Spleen cells from adult specific pathogen-free miniature swine were exposed to sheep red blood cell (SRBC) 2 monolayers to follow the course of the immune response to immobilized particulate antigen. Spleen cells in medium were incubated for various time intervals on the monolayers, removed and cultured in new dishes without further exposure to SRBC antigen for 5.5 days. Spleen cells from unimmunized "normal" animals responded maximally with 6-h exposure to a monolayer consisting of 75% SRBC and 25% autologous pig red blood cells. Spleen cells from SRBC primed animals also responded optimally to monolayers of 75% SRBC but required only 2-h exposure before culturing. Only minimal numbers of SRBC were released from the monolayers, and carryover of antigen from the monolayer to the fresh tissue culture dishes was not a factor in promoting response. This method of in vitro immunization provides for pulse exposure to particulate antigen and facilitates precise evaluation of the role of antigen during the course of the immune response.

Animals↗
PubMed1980

Inhibition of the immune response by Fc receptor-bound specific antibody on T lymphocytes.

Removal of naturally occurring membrane-bound antibody from the surface of nonadherent spleen cells by pronase enhances the in vitro plaque-forming cell response to sheep erythrocytes, and this enhancement can be abrogated by preincubation of the enzyme-treated cells in anti-sheep red blood cell antibody. This inhibitory effect is specific in that prior absorption with sheep erythrocytes but not with noncross-reacting red blood cells removes the activity from antibody-containing preparations. Whole IgG molecules are necessary to bind to Fc receptor; F(ab')2 fragments do not inhibit. The functionally significant Fc receptor-bound antibody in this system is found on the T lymphocyte.

Animals↗
PubMed1978

Inhibition of the immune response by membrane-bound antibody.

Cells from the spleens of "normal" swine, which were pretreated with pronase to remove surface membrane-bound immunoglobulin, gave an enhanced hemolytic plaque-forming cell response to sheep red blood cells in vitro in comparison with untreated controls. The enhancement could be abrogated by preincubating pronase-treated spleeen cells in preparations containing antibody to sheep red blood cells. This effect was demonstrated by autologous sera, immune sera, and all three known classes of porcine serum immunoglobulins, including IgM, IgA, and IgG and could be removed by absorption with sheep red blood cells. Surface membrane-bound antibody exerted its effect by binding to the nonadherent cell population. The response of normal spleen cells was unaffected by antibody treatment. Pronase-treatment was not mitogenic, did not function as a polyclonal B cell activator, and did not selectively eliminate T or B cells. The results indicate that removal of antibody from the surface of lymphoid cells enhanced the humoral immune response invitro and confirm that membrane-bound antibody can inhibit response to antigen.

Animals↗
PubMed1977

Escape from antibody-mediated immune suppression in vitro by delayed-type hypersensitivity reaction.

Anti-sheep erythrocyte antiserum suppressed the in vitro immune response of swine spleen cells to sheep erythrocytes. Inhibition of the in vitro anti-sheep erythrocyte response was also observed in neonatal spleen cells, which were obtained from piglets recently fed colostrum. Addition of purified protein derivative (PPD) to spleen cell cultures prepared from animals previously sensitized to Mycobacterium bovis reversed the immunosuppression caused by passive antibody. Passive antibody regulation was dose dependent; low doses of anti-sheep erythrocyte antiserum caused enhancement, whereas higher doses resulted in complete inhibition of anti-sheep erythrocyte responses. Addition of PPD to cultures of sensitized cells containing passive antibody resulted in progressively increased antibody responses as the dose of anti-sheep erythrocyte antibody increased. PPD addition also reversed maternal antibody suppression of in vitro 2-week-old neonatal spleen cell responses providing these animals were sensitized with M. bovis at the time of birth.

Animals↗
PubMed1977

Regulation of the immune response in neonatal piglets by maternal antibody.

The ability of maternal antibody to regulate the humoral immune response to sheep erythrocytes and the hapten-carrier conjugate trinitrophenylated sheep erythrocytes (TNP-SRBC) was investigated in neonatal piglets. It was found that in this system, passively acquired maternal antibody would completely inhibit the in vitro primary immune response to SRBC while leaving the response the TNP intact. Data suggest that maternal antibody is regulating the in vitro response at the B-cell level since T-cell helper function to SRBC must not have been inhibited in order for an anti-TNP response to have occurred to TNP-SRBC. The regulation of immune responses by maternal antibody is temporary and disappears before 3 months of age.

Aging↗
PubMed1976

Variability of the immunological state of germfree colostrum-deprived Minnesota miniature piglets.

Minnesota miniature piglets obtained by hysterectomy and deprived of colostrum were examined for the presence of immunoglobulin by immunoelectrophoresis, double-gel diffusion, and radial immunodiffusion techniques with specific anti-immunoglobulin chain sera. A large amount of variability existed between different litters of piglets and between different piglets within the same litter, ranging from no detectable immunoglobulin in the serum to very high immunoglobulin levels approaching that of the adult pig. All known classes of porcine immunoglobulin including immunoglobulin G, immunoglobulin M, and immunoglobulin A could be found in the sera from litters where there was extensive placental damage. This contaminating immunoglobulin was shown to have antibody activity to actinophage MSP-2 even when present in very low concentrations. The low level contamination with immunoglobulin G, which was the most frequently encountered type of contaminant, was demonstrated to be similar to sow immunoglobulin G both antigenically and in its molecular size. The data demonstrates that individual piglets must be tested for immunoglobulin content rather than being assumed to be immunologically "virgin" and emphasizes the need for an intact placenta barrier to obtain piglets free from maternal immunoglobulin and devoid of antigenic stimulation.

Animals↗
PubMed1976

Enhancement of humoral immune responses. I. Potentiating influence of purified protein derivative on the invitro immune response of spleen cells sensitized to Mycobacterium bovis and Mycobacterium avium.

Addition of purified protein derivate (PPD) to suspension cultures of spleen cells from swine sensitized to Mycobacterium bovis and Mycobacterium avium resulted in marked enhancement of antisheep erythrocyte plaque-forming cells after stimulation with sheep erythrocytes. The enhancing effect appeared early in the response and was specific for the sensitizing antigen. The enhancing effect was dependent upon the presence of both sheep erythrocytes and PPD in the culture system. PPD had no effect in the absence of sheep erythrocytes. Addition of PPD to cells from nonsensitized animals did not produce any enhancing effect.

Adjuvants, Immunologic↗