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Biomedical subjects

M Perkus

Publications and source records attributed to M Perkus.

4 recordsLinked to original sources
PubMed2001

DNA prime/canarypox boost-based immunotherapy of chronic hepatitis B virus infection in a chimpanzee.

There are about 200 million chronic hepatitis B virus (HBV) carriers at high risk of development of cirrhosis and hepatocellular carcinoma. Termination of the carrier state may avert these risks. We have investigated immunotherapy for chronic HBV infection in a chimpanzee HBV carrier using recombinant DNA-based immunization followed by a recombinant canarypox booster. One week after the booster, HBV DNA declined greater than 400-fold and remained undetectable by the quantitative polymerase chain reaction (PCR) assay for 186 weeks. Plasma levels of hepatitis B surface antigen (HBsAg) declined for only a short time. The decline in HBV DNA correlated with a boost in gamma interferon production without a corresponding boost in cytotoxic T lymphocyte levels, and decline in the transcriptional template or covalently closed circular DNA level. Confirmation of these findings requires further studies in chimpanzees and/or in humans.

Alanine Transaminase↗
PubMed1998

Hepatitis C virus-specific CTL responses in PBMC from chimpanzees with chronic hepatitis C: determination of CTL and CTL precursor frequencies using a recombinant canarypox virus (ALVAC).

The aim of this study was to evaluate HCV-cytotoxic T lymphocyte response from PBMC in bulk CTL assays and in CTL precursor analyses using in vitro stimulation with canarypox virus (ALVAC) expressing HCV-capsid/E1/E2/NS2/NS3 antigens. Canarypox virus is naturally host-range restricted and does not replicate or cause cytopathology on mammalian cells. PBMC were obtained from four chimpanzees with chronic hepatitis C infection and one uninfected chimpanzee. CTL from bulk culture of PBMC and CTL precursor frequencies were found in three of the four chronically infected chimpanzees using ALVAC in vitro stimulation. No CTL response was detected in PBMC from the uninfected chimpanzee. The precursor frequencies of CTL specific for capsid, NS2 and NS3 proteins ranged between 1/2663 and 1/27202. No correlation was observed between percent cytolysis in bulk culture and CTL precursor frequencies. This method may prove useful in assessing the correlation between HCV-CTL response and virological or histological status.

Animals↗
PubMed1986

Response of dairy calves to vaccinia viruses that express foreign genes.

Repeated intradermal inoculations of calves with wild-type vaccinia virus and recombinant vaccinia viruses expressing human hepatitis B virus surface antigen and herpes simplex virus, type 1, glycoprotein D produced characteristic pox lesions at each site of injection. In some instances, calves were inoculated as many as five times at intervals from 4 to 7 weeks. The lesions invariably were more severe after the second inoculation. Subsequent inoculations produced a less severe area of redness, swelling, necrosis, and scab formation. No other signs of illness, such as an elevation in temperature, were noted in the calves. Vaccinia virus was isolated in low titers from scabs taken at various times after inoculation. No lesions were formed at the sites injected with tissue culture fluid and cellular debris at the same time that virus inoculations were made. Calf contact controls remained normal through the 8-week exposure in isolation units with calves inoculated twice with vaccinia virus. No neutralizing antibody to vaccinia virus was detected in the contact controls. In contrast, the virus-inoculated calves developed neutralizing antibody to vaccinia virus and to herpes simplex virus glycoprotein D in serum. In all cattle, a second inoculation significantly enhanced the neutralizing antibody response within 1 week, suggesting that an anamnestic response had occurred. No antibody to hepatitis B virus surface antigen was elicited in calves after repeated inoculations with vaccinia recombinants that express hepatitis B virus surface antigen and are known to elicit in rabbits antibodies reactive with hepatitis B virus surface antigen.

Animals↗