ANTIBODY RESPONSES TO THE CELLULAR PROTEINS OF A LOCAL STRAIN OF STREPTOCOCCUS PNEUMONIAE

AUTHOR: OGBODO, JOHN UCHENNA

DEPARTMENT: PHARMACEUTICAL MICROBIOLOGY & BIOTECHNOLOGY

AFFILIATION: NNAMDI AZIKIWE UNIVERSITY, AWKA

Protein antigens from Streptococcus pneumoniae offer great potentials as possible vaccine candidates to circumvent most of the shortcomings associated with the present pneumococcal vaccines which are based on polysaccharides. The goal of this study is to differentiate the individual contributions of Immunoglobulin G1 (IgG1) and (IgG2a) antibody isotypes to protein antigen induced
immunity against pneumococcal infections. A strain of Streptococcus pneumoniae isolated from a sputum sample at the University of Nigeria Teaching Hospital Ituku-Ozalla was lysed by chemical treatment to liberate the cellular protein. Three groups of mice were immunized subcutaneously with 50, 75, and 100 μg respectively of the protein, and given a boost immunization 7 days later with similar doses of the cellular proteins. The levels of serum total IgG, IgG1, and IgG2a responses to the proteins in mice were determined using Enzyme Linked Immunosorbent Assay (ELISA) technique. The protein elicited a dose dependent response (p≤0.01) for the three immunoglobulin isotypes probed; however IgG1 isotype response was higher than IgG2a responses. The highest response was obtained at a dose of 50 μg. To determine the level of protection offered by the antibodies developed, the mice were challenged intranasally and intraperitoneally with 5 x 105 and 1×104 CFUs of Streptococcus pneumoniae respectively. The outcome showed that the antibodies offered significant protection (p≤0.01) against nasal colonization and sepsis. The study also confirmed the dominance of Th2 response in the protection against nasal colonization and sepsis.

TO VIEW THE FULL CONTENT OF THIS DOCUMENT, PLEASE VISIT THE UNIZIK LIBRARY WEBSITE USING THIS LINK,

Advertisements

Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


%d bloggers like this: