The Immunogenicity of γ-irradiated tachyzoites of a highly virulent strain of Toxoplasma gondii (RH strain) was investigated. Immunized mice survived challenge infection and displayed increased interferon gamma (INF-γ ) production. On the other hand, nonimmunized controls died after 10 days and displayed a significantly decreased lymphoproliferative response to Concanavalin A (Con A). No tachyz...

The Babesia bovis merozoite surface antigen 1 (MSA-1) is an immunodominant membrane glycoprotein that is the target of invasion-blocking antibodies. While antigenic variation has been demonstrated in MSA-1 among strains from distinct geographical areas, the extent of sequence variation within a region where it is endemic and the effect of variation on immunologic cross-reactivity have not been ...

Brucella abortus strain RB51 is an attenuated rough strain that is currently being used as the official live vaccine for bovine brucellosis in the United States and several other countries. We reasoned that overexpression of a protective antigen(s) of B. abortus in strain RB51 should enhance its vaccine efficacy. To test this hypothesis, we overexpressed Cu/Zn superoxide dismutase (SOD) protein...

A live bovine viral diarrhea (BVDV) vaccine, marketed as a derivate of the Oregon C24V strain, was used between the end of the 1960s and the beginning of the 1990s in Central Europe. Since laboratory investigations of mucosal disease cases in vaccinated animals suggested recombinations between the vaccine and wild type variants of BVDV, and recombinational nucleotide sequences seemed distinct f...

Safety and immunogenicity of Brucella abortus RB51 vaccine has been evaluated in an organised dairy farm in India. All the cattle (r = 29) vaccinated with strain RB51 'responded' to the vaccine as demonstrated by iELISA using acetone killed strain RB51 antigen. The percentage responders at day 35, 60 and 90 post vaccination were 100%, 95% and 20%, respectively. Strain RB51 was able to elicit a ...

Live, attenuated bacteria are effective vectors for heterologous antigen delivery. However, loss of heterologous gene-bearing plasmids is problematic, and antibiotics and their resistance genes are not desirable for in vivo DNA vaccine delivery due to biosafety and regulatory concerns. To solve this problem, we engineered the first vaccine delivery strain that has no requirement for antibiotics...

Due to variations in serotypes among different strains of avian infectious bronchitis viruses (IBV), vaccination of chicks with imported vaccines fails to protect them from IBV infections in Taiwan. Therefore, we develop attenuated vaccines from local strains in Taiwan. A Taiwan Group I (TW I) strain was passaged 74 times through specific pathogen-free (SPF) chicken embryonated eggs, and then t...

A live oral cholera vaccine developed from a non-toxigenic Vibrio cholerae O1 El Tor strain VA1.3 was tested in a double-blind randomized placebo controlled study for safety and immunogenicity in 304 men aged between 16 and 50 years from Kolkata, India. A dose of 5 x 10(9)CFU (n=186) or a placebo (n=116) containing the diluent buffer was administered. The vaccine did not elicit adverse events e...

Since influenza may be prevented by vaccine, development and successful implementation of public health programs to prevent spread of a potential avian influenza strain relies upon vaccination as a strategic cornerstone. Although both the Department of Health and Human Services (HHS)† and the World Health Organization (WHO) highlight the role of influenza vaccination as the core of an effective...