Genetic analysis of generation of serum interferon by bacterial lipopolysaccharide

Administration of bacterial lipopolysaccharides (LPS) to mice causes interferon (IF) to appear in their blood stream. The generation of this serum IF is 'early' and its maximum concentration appears 2 hr after an inoculation of a single optimal dose of LPS (100 μg). Two inbread strains of mice differing in their ability to generate LPS-induced serum IF were used: a high responder strain (C3H/eB), which generates high levels of IF (about 100 IF units/ml serum), and a low responder strain (C3H/HeJ), which fails to generate any detectable amounts of IF in the serum. A genetic analysis was carried out and circulating IF production was determined in the F₁ hybrid, in the F₂ generation, and in the progeny of backcrosses of F₁ hybrids to either parent strain. The results indicate that a single dominant autosomal gene is responsible for the difference in circulating IF production between both parent strains. In addition it was shown that this type of IF is stable to treatment at pH 2 for periods of time as long as 48 hr, but is labile to heating at 56°C for 30 min.