A multimeric form of soluble recombinant sheep LFA-3 (CD58) inhibits human T-cell proliferation.
The rosetting of T cells by sheep erythrocytes is mediated through the interaction of the CD2 molecule on T cells with T11TS, a molecule on sheep erythrocytes homologous to lymphocyte function-associated antigen-3 (LFA-3, CD58). We cloned a T11TS cDNA from sheep leucocyte mRNA which encodes a soluble molecule comprising the distal D1 and the D2 extracellular domains, but not the transmembrane domain. cDNA for this soluble D1 + D2 form of sheep LFA-3 (sLFA-3) was expressed in Escherichia coli and the properties of the purified recombinant protein were assessed by inhibition of T-cell rosette formation. sLFA-3 inhibited rosette formation, but its activity was low, 50% inhibition occurring at 25 micrograms/ml, consistent with the observed low binding avidity of fluorescein isothiocyanate (FITC)-labelled sLFA-3, sLFA-3 was made multimeric to increase its affinity, by crosslinking biotinylated sLFA-3 to streptavidin-biotinylated dextran complexes. The binding of crosslinked sLFA-3 multimers, tested by fluorescence-activated cell sorting (FACS) analysis, was significantly increased compared to sLFA-3 monomers. Competition with monoclonal antibodies demonstrated that multimeric sLFA-3 bound to the T11(1) epitope on CD2. The multimeric form of sLFA-3 was significantly more potent than the monomer in inhibiting proliferation of human T cells in response to purified protein derivative (PPD), tetanus toxoid (TT) or allogeneic cells. Multimeric sLFA-3 might, therefore, have potential as an immunotherapeutic agent to inhibit and/or anergize antigen-specific T-cell responses.
Yamashita
K
K
Kaneka Corporation, Takasago Research Laboratories, Hyogo, Japan.
Parish
C R
CR
Warren
H S
HS
Harrison
L C
LC
D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism; D018801:CD2 Antigens / Q000378:metabolism; D018968:CD58 Antigens / Q000235:genetics / Q000276:immunology*; D002455:Cell Division / Q000276:immunology; D018076:DNA, Complementary / Q000235:genetics; D000939:Epitopes / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D007108:Immune Tolerance; D008213:Lymphocyte Activation / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology; D012397:Rosette Formation; D012756:Sheep; D012995:Solubility; D013601:T-Lymphocytes / Q000276:immunology*
D000954:Antigens, Surface; D018801:CD2 Antigens; D018968:CD58 Antigens; D018076:DNA, Complementary; D000939:Epitopes; D011994:Recombinant Proteins