Monoclonal antibodies specific for apoproteins of lipophorins from the migratory locust

Spleen lymphocytes from mice immunized with locust native low‐density lipophorin A+ (LDLp) were fused with nonproducing myeloma cells, strain Sp 2/0. Hybridomas that were isolated from the fused cells produced antibodies specific for LDLp and the high‐density lipophorin Ayellow (HDLp). Monoclonal strains were generated through cloning by limiting dilution from those hybridomas synthesizing antibodies specific for apolipophorins (apoLp)‐I, ‐II, and ‐III of LDLp. Additionally, a hybridoma strain that was obtained after fusion of lymphocytes from mice immunized with apoLp‐III produced antibodies that bind to apoLp‐III and native LDLp. Some features of LDLp and HDLp were studied using these antibodies. It could be demonstrated that apoLp‐I and apoLp‐II are not immunochemically identical and are exposed in the native particle of both LDLp and HDLp. It was also shown that in both lipophorins apoLp‐II is less exposed than apoLp‐I, whereas in LDLp apoLp‐III is mainly exposed; some apoLp‐III could also be detected in HDLp. Tween‐20, a nonionic detergent, appears to affect the binding of anti‐apoLp‐I, ‐II, and ‐III to both LDLp and HDLp. The monoclonal antibodies specific for locust apolipophorins do not bind to the respective apoproteins of lipophorins from other insects.