Replacement of primary monkey kidney cells by L20B cell line in the test for effective inactivation of inactivated poliovirus vaccine.

Absence of 'live' residual poliovirus in Inactivated Poliovirus Vaccine (IPV) is routinely checked using Primary Monkey Kidney Cells (PMKC). However, the increasing demand for IPV and the ethical, technical and safety issues associated with the use of non-human primates in research and quality control, has made the replacement of primary cells with an established cell line a priority, in line with the principles of the 3Rs (Replacement, Reduction and Refinement in animal testing). As an alternative to PMKC, we evaluated the L20B cell line; a mouse cell-line genetically engineered to express human poliovirus receptor, CD155.

Development and validation of high-performance size exclusion chromatography methods to determine molecular size parameters of Haemophilus influenzae type b polysaccharides and conjugates.

Current vaccines against Haemophilus influenzae type b (Hib) consist of the polyribosyl ribitol phosphate (PRP) capsular polysaccharide chemically conjugated to a carrier protein. Among the various biological and physical analyses to be performed on these vaccines, the determination of the molecular size of the polysaccharide preparations throughout the conjugation process is particularly relevant. Comparison of results from high-performance size exclusion chromatography (HPSEC) with those routinely obtained using conventional gel permeation chromatography (CGPC) methods highlights the correlation between the two methods for determining the values of the chromatographic distribution coefficient (KD) of native and activated polysaccharides.

Immunogenicity of a hexavalent combination vaccine in rhesus monkeys.

Preclinical immunogenicity studies were conducted in rhesus monkeys to determine whether there is immune interference in the response to one or more components of a hexavalent vaccine (Hexavac) that contains antigens from Haemophilus influenzae (Hib), hepatitis B (HB), diphtheria (D), tetanus (T), acellular pertussis (aP) and inactivated polio virus (IPV). Antibody responses were measured following co-administration of the components at three separate anatomical sites or administration as a hexavalent combination in a single site. After three injections of the hexavalent vaccine, the peak antibody responses to each component of the vaccine were >100-fold above pre-immune titers and persisted at levels >10-fold above pre-immune titers at approximately 1 year.

Typing of rabies virus isolates by DNA enzyme immunoassay.

Background: Alternatives to antigenic typing are needed for epidemiologic surveys of the rabies virus associated with translocated coyotes and foxes, especially in areas where a closely related rabies virus is transmitted by striped skunks.

Objectives: We developed and evaluated two enzyme based typing methods for rabies virus. The products of a reverse transcription-polymerase chain reaction (RT/PCR) of the nucleoprotein gene were hybridized to type specific probes and detected by enzyme assay after immobilization on microtiter plates.

Effect of antivenom on venom pharmacokinetics in experimentally envenomed rabbits: toward an optimization of antivenom therapy.

Antivenomous immunotherapy is still used empirically. To improve the efficacy and safety of immunotherapy, we studied the effects of administering antivenom antibodies (F(ab')2) on the pharmacokinetics of the Vipera aspis venom in rabbits. Free venom levels were measured by enzyme-linked immunosorbent assay and total concentrations were quantified by measuring the radioactivity of trichloroacetic acid-precipitable radioiodinated venom.