Efficacy of a flexible schedule for administration of a Leptospira borgpetersenii serovar Hardjo bacterin to beef calves.

Objective: To determine whether a flexible vaccination regimen provides protection against challenge exposure with a virulent Leptospira borgpetersenii serovar Hardjo isolate.

Animals: Fifty-five 4-week-old calves seronegative for antibodies against L borgpetersenii serovar Hardjo.

Procedures: Calves were assigned to 3 groups and administered 2 doses of adjuvant (control calves; n = 11), 1 dose of serovar Hardjo bacterin and 1 dose of adjuvant (22), or 2 doses of the serovar Hardjo bacterin (22); there was a 16-week interval between dose administrations.

Identification of streptococcal m-protein cardiopathogenic epitopes in experimental autoimmune valvulitis.

The M protein of rheumatogenic group A streptococci induces carditis and valvulitis in Lewis rats and may play a role in pathogenesis of rheumatic heart disease. To identify the epitopes of M5 protein that produce valvulitis, synthetic peptides spanning A, B, and C repeat regions contained within the extracellular domain of the streptococcal M5 protein were investigated. A repeat region peptides NT4, NT5/6, and NT7 induced valvulitis similar to the intact pepsin fragment of M5 protein.

A review of the effectiveness of vaccine potency control testing.

The use of potency control testing is a valuable tool for testing the actual relative strength of manufactured assembly lots of vaccine. Biological-based manufacturing methods are inherently variable and potency testing is a tool to ensure lot-to-lot consistency of commercial vaccines. A strong historical link to clinical efficacy has been established where correlation to efficacy and adequate test validation have been achieved.

Induction of myocarditis and valvulitis in lewis rats by different epitopes of cardiac myosin and its implications in rheumatic carditis.

Immune responses against cardiac myosin and group A streptococcal M protein have been implicated in the pathogenesis of rheumatic heart disease. Although cardiac myosin is known to produce myocarditis in susceptible animals, it has never been investigated for its role in production of valvular heart disease, the most serious sequelae of group A streptococcal infection in acute rheumatic fever. In our study, cardiac myosin induced valvulitis in the Lewis rat, and epitopes responsible for production of valvulitis were located in the rod region.