Anti-tumor activity of a peptide combining patterns of insect alloferons and mammalian immunoglobulins in naïve and tumor antigen vaccinated mice

•A peptide combining insect alloferon and mammalian immunoglobulin patterns was constructed.•The peptide and alloferon anti-tumor activity was tested in mouse tumor transplantation model.•The peptide show superior activity in naïve and particularly in tumor antigen vaccinated mice.•The peptide counterpart is omnipresent in human and mouse immunoglobulins.•The peptide and alloferon-1 are worthy of consideration as potential anti-cancer drugs.

Alloferons are a group of naturally occurring peptides primarily isolated from insects and capable of stimulating mouse and human NK cell cytotoxicity towards cancer cells. In this paper we examined anti-tumor activity of alloferon-1 and its novel structural analog referred to as allostatine. The activity was tested in naïve and preventively tumor antigen vaccinated DBA/2 mice subcutaneously grafted with syngenic P388D1 mouse leukemia cells. In naïve animals allostatine demonstrated tumoristatic activity prevailing over alloferon-1 effect. The preventive vaccination caused only weak tumoristatic effect in 27% of vaccinated animals. The vaccination efficacy was dramatically enhanced by allostatine but not alloferon-1 administration: 65% of allostatine treated animals benefitted from tumoristatic effect and 30% was completely cured so that total number of positive responders grew to 95%. Thus, alloferon-1 and especially allostatine are worthy of further consideration as potential anti-cancer drugs. Allostatine seems to be particularly perspective for adjuvant cancer immunotherapy. Sequence similarity search revealed evolutionary conserved allostatine-like pattern inserted to CDR3 region of human and mouse immunoglobulins. By analogy with allostatine, the pattern may execute some unknown so far function in anti-tumor immune response regulation.