Lipoproteina in the chimpanezee: relationship of apoa phenotype to elevated plasma Lpa levels.

Several studies have documented the presence of Lpa in nonhuman primates. However, data are lacking in great apes such as the chimpanzee. We have studied the quantitative distribution of Lpa, as well as the frequency of apoa phenotypes, in a population of chimpanzees living in Gabon. Monoclonal antibody 14A12, directed against human apoa, failed to recognize chimpanzee Lpa. Therefore, Lpa was assayed using an ELISA involving two polyclonal antibodies, an anti-human apoa and an anti-human apoB-100. Under these conditions, Lpa was detected in each of 28 animals. The plasma level of Lpa was found to be highly skewed toward elevated values: the mean Lpa level was 0.61 mg/ml (SD 0.45) as compared to 0.18 mg/ml (SD 0.16) in a normal Caucasian population (P < 0.0001). Phenotypes for apoa were identified by SDS-agarose-gel electrophoresis, followed by immunoblotting and detection by chemiluminescence. Seventeen different isoforms (ranging from 440 to 920 kDa) were found among all the animals as compared to 19 (540 to 960 kDa) in a human population of equivalent number. However, the distribution of apoa phenotypes was distinct between these populations. Thus isoforms of low molecular mass occurred with greater frequency in chimpanzee as compared to humans. In both populations, a strong inverse correlation between Lpa levels and apoa isoform sizes was found in chimpanzees (r = -0.48; P < 0.01) and in man (r = -0.68; P < 0.0002).(ABSTRACT TRUNCATED AT 250 WORDS)