ISSN:
1365-3083
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
We have studied the interaction of mitogenic lectins such as phytohaemagglutinin (PHA) and concanavalin A (Con A) with both surface molecules which, by the use of monoclonal antibodies, are known to trigger T-cell mitogenesis. Monoclonal antibodies recognizing the T-lymphocyte receptor for antigen (Ti) and/or its associated structure, CD3, activate T cells. More recently, a second pathway of activation has been described which involves the sheep erythrocyte binding glycoprotein CD2. a surface molecule distinct from Ti-CD3. Lysates from surface-iodinated T-leukaemia cell lines were treated with lectin and affinity purified anti-lectin antibodies coupled to protein A-Sepharose. We have shown that eluatcs from Con A/anti-Con A or PHA/anti-PHA immunoprecipitates contained Ti. since;a rabbit anti-Tα serum, which recognises the native and denatured forms of the constant region of the α chain, immuno-precipitated Ti from these eluates. Furthermore, Ti immunoprecipitalcd bv anti-Tα serum from lysates of surface iodinated E lymphocvtes was binding to PHA after elution from the immunoprecipitate. When the purified Ti molecule was reduced and alkylated, allowing the permanent dissociation of its α and β subunits, PHA interacted with both chains, whereas anti-Tα serum immunoprecipitalcd the α chain onlv. Altogether, these results demonstrate that PHA interacts with both chains of the T cell receptor for antigen on human peripheral T lymphocytes. With the HPB-ALL tumour line, a similar approach showed that both α and β chains of Ti bind to Con A and Ulex europtaeus- 1 but not Helix pomatia. Affinity chomatographv on immobilized lectins and immunoprecipitation with lectin/anti-leelin antibodies were employed to test whether CD2 binds to PHA and Con A. The results show that CD2 from human peripheral T lymphoevtes binds both lectins but with a lower affinity for PHA than Con A.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-3083.1986.tb01985.x
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