Chemotactic Anti-Tumour Antibodies: In Vitro Results with Four Different Antibody Preparations

Abstract

The biological behaviour and prognosis of a tumour may be related to the number of intratumour inflammatory cells. However, based on retrospective analysis, tumour infiltrating inflammatory cells have been associated with suppression of metastasis¹, or, to the contrary, enhancement of tumour growth². Recently, we demonstrated that prospective enhancement of tumour infiltrating macrophage numbers in vivo is possible by the administration of anti-tumour heteroantibodies covalently coupled to the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (fMLP)³. Using mouse monoclonal antibodies (moab), which have the advantages of being of one molecular species only and of virtually unlimited supply, a more strict evaluation of the biological role of tumour infiltrating macrophages might therefore become feasible. We already demonstrated in vitro chemotactic activity and antigen recognition function of moab-fMLP conjugates similar to the hetero-antibody-fMLP conjugate^4,5. Whereas a similar average number of binding sites can be assumed for different polyclonal antibodies, conjugation of fMLP to moab is limited by the available number of binding sites on the given moab molecule, which might differ from one moab species to another. In this paper, the in vitro chemotactic activity of polyclonal IgM and IgG conjugates and of three different moab-conjugates is compared.