Henry Z. Markus

Sequence conservation within the major capsid protein of human papillomavirus (HPV) type 18 and formation of HPV-18 virus-like particles in Saccharomyces cerevisiae

The major capsid protein L1 of human papillomaviruses (HPVs) has been identified as a promising candidate antigen for a prophylactic HPV vaccine. Since amino acid sequence heterogeneity has been demonstrated for the L1 genes within individual HPV types, nucleotide sequences of L1 were determined from six HPV-18 clinical isolates and the cervical carcinoma cell line SW756 and compared to the published HPV-18 prototype sequence. The sequences were almost identical between the clinical isolates and SW756 but differed markedly from the published prototype sequence. Resequencing the prototype HPV-18 revealed that these differences were due to sequencing artifacts of the prototype HPV-18 sequence archived in GenBank. Thus, the HPV-18 L1 genes seem to display a very high level of sequence conservation. The HPV-18 L1 gene derived from SW756 was expressed in Saccharomyces cerevisiae and self-assembly of the L1 protein into virus-like particles was demonstrated.

Production of purified hepatitis B surface antigen from Alexander hepatoma cells grown in artificial capillary units

An artificial capillary system was devised for growth of hepatoma cells that yields very high titers of hepatitis B surface antigen (HBsAg). High yield of antigen was facilitated by slowing cellular metabolism through reduction of incubation temperature and addition of 0.1 mM caffeine. Deletion of serum from the medium did not reduce the yield of antigen. HBsAg prepared from the culture fluid by affinity chromatography and additional chemical and enzymatic steps was essentially pure and was indistinguishable from HBsAg prepared from infected human plasma. Preparation of HBsAg from the cell culture source presents advantages over that of human plasma and might be a source of HBsAg for vaccine preparation.

A novel single-dose delivery system for vaccines

A single-dose, low-cost vaccine delivery system (Ezeject®) consisting of lyophilized measles (Moraten—Attenuvax®) vaccine loaded into a pre-filled single-dose plastic syringe with a squeezable body portion has been developed in these laboratories. Data concerning the preparation and properties of vaccine-filled plastic syringes and the findings in clinical tests are presented in this report.