Monoclonal Antibodies Against Human Growth Hormone Releasing Factor,hGRF(1–44)NH 2

Abstract

Eleven hybridomas secreting monoclonal antibodies (MAb) against amidated human growth hormone releasing factor, hGRF(1–44)NH₂ have been produced by the cellfusion technique. Isotyping of the MAbs revealed that ten MAbs belong to the class IgG1 and one to the class IgG3.

All light chains belong to the ψ group. The specificity and relative avidity of these MAbs have been determined using an indirect enzyme-linked immunosorbent assay. Nine antibodies exhibit a relatively high avidity for hGRF(1–44)NH₂, one is of intermediate avidity and one of low avidity. The epitope specificity of the MAbs, originating from two different mice lines, has been examined in inhibition experiments. All MAbs, except one, display a similar inhibition pattern, suggesting that they recognize the same antigenic determinant. Partial inhibition effects displayed by the last MAb seem to be related to its low affinity for the antigen. Experiments using a shorter, non-amidated form of the antigen, hGRF(1–40)OH, suggest that all MAbs recognize the C-terminal part of hGRF(1–44)NH₂.