Molecular and antigenic heterogeneity of the rat leukocyte‐common antigen from thymocytes and T and B lymphocytes

Abstract

The molecular forms and antigenic heterogeneity of the leukocyte-common antigen (L-CA) of rat lymphocytes have been analyzed. Thymocytes show one main band at 180 kDa, T cells four bands at 180, 190, 200 and 220 kDa and B cells one broad band at about 240 kDa. T helper and T cytotoxic cell subsets show the same four bands with some differences in the proportion of each. Four mouse monoclonal antibodies (MRC OX-1, 28, 29 and 30) reacted with all molecular forms of L-CA and fell into two sets that were noncompetitive in binding to L-CA (MRC OX-1, 28, 29 vs. OX-30). The antigenic determinants seen by all these antibodies were lost when L-CA was reduced and alkylated. Three antibodies (MRC OX-22, 31 and 32) reacted selectively with B cells, T cytotoxic cells and about 2/3 of T helper cells. OX-22 and OX-31 competed for binding but were noncompetitive with OX-32. All these antibodies bound to a subfraction of the 190, 200 and 220-kDa forms of T cell L-CA but not at all to the 180-kDa form of T cells or thymocytes. One antibody bound to B cells only (MRC OX-33) and precipitated a subfraction of B cell L-CA. With all the antibodies that did not label thymocytes the antigenic determinants survived reduction and alkylation. Subsequent proteolysis with trypsin then destroyed all determinants except the one reacting with MRC OX-22 antibody. In this case tryptic peptides retained full antigenic activity which was, however, destroyed by further proteolysis with pronase.

CD4+ T cells from 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis rodents migrate to the recipient's colon upon transfer; down-regulation by CD8+ T cells

“…ED1 recognizes CD68 [25,26], OX19 is a T cell marker which recognizes CD5 [27], OX33 is a B cell marker which recognizes CD45RA or A/B [28,29], and HIS41 recognizes RT7.2 of the L-CA (or CD45) [23].…”

Inflammatory cells, microglia and MHC class II antigen-positive cells in the spinal cord of Lewis rats with acute and chronic relapsing experimental autoimmune encephalomyelitis

“…The following monoclonal antibodies were obtained from Serotec and by kind donation from Dr J. Sedgwick: R73 (αβ T cell receptor) (Hünig et al, 1989), OX34 (CD2 on T cells and natural killer (NK) cells) , OX39 (IL-2R) , OX22 (CD45RC, the high molecular mass form of the leukocyte common antigen on B cells, macrophages and some T cells) (Spickett et al, 1983;Woollett et al, 1985), OX8 (CD8 on MHC class I restricted T cells and some NK cells) (Brideau et al, 1980), W3/25 (CD4) (White et al, 1978), OX33 (B cells) (Woollett et al, 1985), OX12 (kappa light chains) (Hunt and Fowler, 1981;Barclay, 1981a), OX6 (MHC class II) Barclay, 1981b); OX42 (CD11b) (Robinson et al, 1986) and OX1 (leukocyte common antigen on all cells of haemopoietic origin) (Sunderland et al, 1979).…”

Regulation of tissue-specific alternative splicing: exon-specific cis-elements govern the splicing of leukocyte common antigen pre-mRNA.

“…During the differentiation of T cells, the splicing pattern of the LCA gene changes in a complex manner. Thymocytes express an LCA encoded by mRNA that lacks exons 4, 5 or 6 (Morimoto et al, 1985a;Woollett et al, 1985;Lefrancois et al, 1986;Streuli et al, 1988b). As thymocytes mature, a subset of T cells develop that express LCA encoded by mRNA that includes exons 4, 5 and 6.…”