De. Briles et al., PNEUMOCOCCAL DIVERSITY - CONSIDERATIONS FOR NEW VACCINE STRATEGIES WITH EMPHASIS ON PNEUMOCOCCAL SURFACE PROTEIN-A (PSPA), Clinical microbiology reviews (Print), 11(4), 1998, pp. 645
Streptococcus pneumoniae is a problematic infectious agent, whose seri
ousness to human health has been underscored by the recent rise in the
frequency of isolation of multidrug-resistant strains. Pneumococcal p
neumonia in the elderly is common and often fatal. Young children in t
he developing world are at significant risk for fatal pneumococcal res
piratory disease, while in the developed world otitis media in childre
n results in substantial economic costs. Immunocompromised patients ar
e extremely susceptible to pneumococcal infection. With 90 different c
apsular types thus far described, the diversity of pneumococci contrib
utes to die challenges of preventing and treating S. pneumoniae infect
ions. The current capsular polysaccharide vaccine is not recommended f
or use in children younger than 2 years and is not fully effective in
the elderly. Therefore, innovative vaccine strategies to protect again
st this agent are needed. Given the immunogenic nature of S. pneumonia
e proteins, these molecules are being investigated as potential vaccin
e candidates. Pneumococcal surface protein A (PspA) has been evaluated
for its ability to elicit protection against S. pneumoniae infection
in mouse models of systemic and local disease. This review focuses on
immune system responsiveness to PspA and the ability of PspA to elicit
cross-protection against heterologous strains. These parameters will
be critical to the design of broadly protective pneumococcal vaccines.