In vitro and in vivo studies of the growth inhibitory effect of a newly synthesized peptide, obiopeptide-1, on mice-bearing methylcholanthrene-induced murine tumours.
Novel synthetic Obiopeptide (Obi-1), Glycil-penta-Glutamate, as an immunoregulator, injected intramuscularly to methylcholanthrene (MC) induced tumour bearing mice at 30-100 micrograms per mouse weekly, significantly inhibited tumour growth, compared to that of the untreated control. Numbers of mononuclear cells (MNC) in the spleen obtained from Obi-1 treated and untreated mice were reduced to 64% and 10% of the normal levels, respectively. In histopathological findings, variations of MNC in the spleen was observed in colonies of large MNC and lymphocytes in Obi-1 treated red marrow, while untreated one showed only scattered number of small lymphocytes. A significant O2- production was noted in monolayers of normal macrophages incubated with 0.5 mg Obi-1/ml for 48 hr. Cytotoxicity of spleen MNC cultured with Obi-1 against MC-tumour, Meth A, P-815 and YAC-1 target cells showed less than 10% cytotoxic activity in almost all experiments.
Sakurai
H
H
Department of Veterinary Physiology, Obihiro University, Hokkaido, Japan.
Fujii
Y
Y
Maki
Y
Y
Igarashi
I
I
Omata
Y
Y
Saito
A
A
Ono
K
K
Suzuki
N
N
D000818:Animals; D000890:Anti-Infective Agents / Q000627:therapeutic use*; D002452:Cell Count / Q000662:veterinary; D007136:Immunoglobulins; D007963:Leukocytes, Mononuclear; D008099:Liver / Q000473:pathology; D008264:Macrophages / Q000187:drug effects; D008748:Methylcholanthrene; D051379:Mice; D008807:Mice, Inbred BALB C; D009374:Neoplasms, Experimental / Q000188:drug therapy*; D010446:Peptide Fragments / Q000627:therapeutic use*; D010529:Peritoneal Cavity / Q000166:cytology; D013154:Spleen / Q000187:drug effects / Q000473:pathology; D013950:Thymus Gland / Q000473:pathology; D014407:Tumor Cells, Cultured
D000890:Anti-Infective Agents; D007136:Immunoglobulins; D010446:Peptide Fragments; C041544:obioactin; D008748:Methylcholanthrene