The potential to use PspA and other pneumococcal proteins to elicit protection against pneumococcal infection

Pneumococcal proteins, alone, in combination with each other, or in combina tion with capsular polysaccharide-protein conjugates may be useful pneumoco ccal vaccine components. Four proteins with a potential for use in vaccines are PspA, pneumolysin, PsaA, and PspC. In a mouse model of carriage, PsaA and PspC were the most efficacious vaccine proteins. Of these, PsaA was the best at eliciting protection against carriage. However, a combination of P spA and pneumolysin may elicit stronger immunity to pulmonary infection and possibly sepsis than either protein alone. Recently, a phase one trial of a recombinant family 1 PspA was completed in man. PspA was observed to be s afe and immunogenic, Injection of 0.1 ml of immune serum diluted to 1/400 w as able to protect mice from fatal infection with S. pneumoniae. Under thes e conditions, preimmune serum was not protective, The immune human serum pr otected mice from infections with pneumococci expressing either of the majo r PspA families (1 and 2) and both of the pneumococcal capsular types teste d: 3 and 6. (C) 2000 Elsevier Science Ltd. All rights reserved.