The immunological role of vaccinia-soluble early antigen was examined in rabbits. The antigens were prepared from HeLa cells infected with a conditional lethal mutant of vaccinia virus, which induces in these cells early antigens including those responsible for surface immunofluorescence of infected cells, but not viral DNA and late protein syntheses. Immunization of rabbits with the antigens in Freund's complete adjuvant induced complement-fixing antibody but neither detectable circulating neutralizing antibody nor any detectable level of inhibitory substance or interferon in the skin of the animals. When immunized animals were inoculated intradermally with vaccinia virus, multiplication of virus in the skin was greatly inhibited, being accompanied by an earlier appearance as well as an accelerated wane of the local reactions. The resistance could not be transferred passively by the serum of immunized animals to normal rabbits. Immunization of rabbits with the antigens without the adjuvant not only failed to inhibit but, contrariwise, enhanced the multiplication of intradermally inoculated vaccinia virus, inducing heavy skin lesions and exalted virus multiplication.

Animals↗

PubMed1973

Isolation and characterization of acid phosphatase mutants in Saccharomyces cerevisiae.

Saccharomyces cerevisiae strain H-42 seems to have two kinds of acid phosphatase: one which is constitutive and one which is repressible by inorganic phosphate. The constitutive enzyme was significantly unstable to heat inactivation, and its K(m) of 9.1 x 10(-4)m for p-nitrophenylphosphate was higher than that of the repressible enzyme (2.4 x 10(-4)m). The constitutive and the repressible acid phosphatases are specified by the phoC gene and by the phoB, phoD, or phoE gene, respectively. Results of tetrad analysis suggested that the phoC and phoE genes are linked to the lys2 locus on chromosome II. Since both repressible acid and alkaline phosphatases were affected simultaneously in the phoR, phoD, and phoS mutants, it was concluded that these enzymes were under the same regulatory mechanism or that they shared a common polypeptide. The phoR mutant produced acid phosphatase constitutively, and the phoR mutant allele was recessive to its wild-type counterpart. The phoS mutant showed a phenotype similar to that of a mutant defective in one of the phoB, phoD, or phoE genes. However, the results of genetic analysis of the phoS mutant clearly indicated that the phoS gene is not a structural gene for either of the repressible acid and alkaline phosphatases, but is a kind of regulatory gene. According to the proposed model, the phoS gene controls the expression of the phoR gene, and inorganic phosphate would act primarily as an inducer for the formation of the phoR product which represses phosphatase synthesis.

Acid Phosphatase↗

PubMed1973