scholarly journals Selective modification of a private I-A allo-stimulating determinant(s) upon association of antigen with an antigen-presenting cell.

1984 ◽  
Vol 159 (4) ◽  
pp. 1238-1252 ◽  
Author(s):  
K L Rock ◽  
B Benacerraf
Keyword(s):  
T Cell ◽  
Interleukin 2 ◽  
Inhibitory Effect ◽  
Stimulator Cell ◽  
Antigen Presenting Cell ◽  
Lymphocyte Cultures ◽  
Nominal Antigen ◽  
Mixed Lymphocyte Cultures ◽  
Antigen Presenting

A large panel of alloreactive, interleukin 2 (IL-2)-producing T cell hybridomas was constructed from B10 alpha BALB/c primary mixed lymphocyte cultures (MLC). Functional hybrids had specificity for either I-Ad or I-Ed. These cells were used to probe determinants on Ia molecules in an attempt to detect molecular association between a nominal antigen and an Ia molecule on an antigen-presenting cell (APC). The response of a small number of these clones was significantly blocked by the addition of the Ir gene-controlled copolymer L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT) to culture. A comparison of the inhibited and uninhibited hybrids revealed an identical dose response curve. Further, both types of hybrids were activated by the same stimulator cell and frequently recognized the identical Ia molecule on that cell. Nevertheless, the inhibitory effect of GAT was localized to the stimulator cell and not to the T cell hybrids. All of the hybrids whose stimulation was blocked had specificity for the I-A molecule, which is the gene product known to control and restrict responsiveness to GAT. Further, only GT, but not a number of other related antigens, was also specifically inhibitory, which correlates with the known associational specificity of these antigens on an APC. Finally, the same stimulator cell could be shown to coordinately lose an allostimulatory determinant(s), while it was gaining an I-Ad plus GAT determinant(s). The implications of these findings on the nature of antigen-Ia association and on the role of polymorphic Ia determinants are discussed.

scholarly journals Inhibition of antigen-specific T lymphocyte activation by structurally related Ir gene-controlled polymers. Evidence of specific competition for accessory cell antigen presentation.

1983 ◽  
Vol 157 (5) ◽  
pp. 1618-1634 ◽  
Author(s):  
K L Rock ◽  
B Benacerraf
Keyword(s):  
Major Histocompatibility Complex ◽  
T Cell ◽  
T Lymphocyte ◽  
Lymphocyte Activation ◽  
Inhibitory Effect ◽  
Accessory Cell ◽  
Histocompatibility Complex ◽  
Accessory Cells ◽  
Nominal Antigen ◽  
Antigen Presenting

The interaction of nominal Ag with major histocompatibility complex (MHC)-restricted T cells and accessory cells was studied by analyzing the effect of structurally related antigens on the response of antigen-specific MHC-restricted T cell hybridomas. The copolymer L-glutamic acid50-L-tyrosine50 (GT) completely inhibits the response of L-glutamic acid60-L-alanine40-L-tyrosine10 (GAT)-specific, I-Ad-restricted T cell hybridomas to GAT plus accessory cells. This inhibition is specific, as hybridomas of other specificities are not inhibited under identical conditions, and is unique to the GT antigen, as other similar copolymers are not inhibitory. The inhibitory effect is reversible by adding increasing amounts of GAT. Antigen-pulsing experiments localized the inhibition to the level of antigen-presenting cell (APC). GT-prepulsed APC are not inhibitory in cell-mixing experiments and can present other antigens. GT only inhibits the nominal antigen-directed component of a GAT-specific, autoreactive hybrid's response. Together these findings suggest that GT causes inhibition by competing for GAT association at the accessory cell. GT interferes with GAT presentation by an I-Adxb F1 APC to a BALB/c, I-Ad-restricted, but not B10, I-Ab-restricted, T cell hybridoma, and GT inhibits presentation by GAT-prepulsed APC. The implications of these findings for MHC-restricted presentation of antigen are discussed.

scholarly journals THYMUS-INDEPENDENT (B) CELL PROLIFERATION IN SPLEEN CELL CULTURES OF MOUSE RADIATION CHIMERAS STIMULATED BY PHYTOHEMAGGLUTININ OR ALLOGENEIC CELLS

1972 ◽  
Vol 136 (4) ◽  
pp. 962-967 ◽  
Author(s):  
P.-F. Piguet ◽  
P. Vassalli
Keyword(s):  
T Cell ◽  
Spleen Cell ◽  
Cell Cultures ◽  
Bone Marrow Cells ◽  
Spleen Cells ◽  
Radiation Chimeras ◽  
Lymphocyte Cultures ◽  
Mixed Lymphocyte Cultures

Spleen cell cultures of radiation chimeras (thymectomized, lethally irradiated mice repopulated with bone marrow cells and thymocytes bearing different chromosomal markers) were stimulated by phytohemagglutinin (PHA) and F1 allogeneic spleen cells. Karyotypic analyses showed a marked predominance of T mitoses on the 2nd and 3rd days of culture followed by a strong predominance of B mitoses on the 4th and 5th days. Analysis of cells undergoing their first mitoses showed that the majority of T mitoses on day 3 resulted from continuous T cell division, and that most cells entering their first mitoses at that time were of B type. Mixed lymphocyte cultures (MLC) of chimeras immunized against allogeneic spleen cells showed sometimes, but not always, a response different from "primary" MLC, with an earlier and stronger predominance of BM mitoses. The role of stimulated T cells in the induction of B mitoses was shown by (a) the incapacity of T-depleted spleen cells to be stimulated by PHA or in primary or secondary MLC, and (b) the restoration of the mitotic response of B cells to PHA by adding to the T cell-depleted culture either a very small number of T cell (identified by their different karyotype: "in vitro chimeras") or the cell-free supernatant of a 24 hr MLC.

scholarly journals Essential role of antigen-presenting cell-derived BAFF for antibody responses

2007 ◽  
Vol 37 (11) ◽  
pp. 3122-3130 ◽  
Author(s):  
Fabio Bergamin ◽  
Isabelle E. Vincent ◽  
Artur Summerfield ◽  
Kenneth C. McCullough
Keyword(s):  
Essential Role ◽  
Antibody Responses ◽  
Antigen Presenting Cell ◽  
Antigen Presenting
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