Comprehensive profiling of antibodies against multiple infectious diseases in serum and the airway mucosa using synthetic peptide-based linear epitope microarrays
Sande C., Chege T., Mutunga M., Gicheru E., Nokes J., Green C., Tuju J.
<h4>Background</h4> Despite the considerable progress that has been achieved in the development of vaccines, infectious diseases continue to be the major cause of morbidity and mortality in developing countries. The first year of life remains the time of greatest risk with more than half of all deaths caused by infectious diseases in children under the age of five years occurring during this period. For most infections, antibodies are the strongest immune correlate of protective immunity and characterizing the breadth of the antibody repertoire against infectious diseases in early life is key to profiling individual disease risk. <h4>Methods</h4> In order to comprehensively profile the antibody repertoire against infectious diseases in early life, we developed a synthetic peptide-based microarray to simultaneously measure antibodies against forty one common infectious diseases. 82 empirically-validated linear B-cell epitopes were selected from the Immune Epitope Database (IEBD), expressed as synthetic peptides and printed onto microarray glass slides (microarray chip). The chip was used to simultaneously measure antigen-specific IgG and IgA in serum and mucosal samples from thirty eight infants and young children presenting to hospital with different illnesses. We also used the data from the microarray to estimate antibody decay kinetics for the five most frequently detected antigens during the first year of life. <h4>Results</h4> A synthetic peptide microarray to measure antibodies against forty one infectious diseases was successfully developed. Although the combination of antigens that were recognized were different for each child, antigens derived from Epstein-Barr virus, poliovirus, Streptococcus pneumoniae , plasmodium falciparum and varicella zoster were recognized by most study participants. While the combination of antigens recognized in serum was generally similar as those recognized in mucosal samples, antibodies to antigens such as herpesvirus, rubella and echinococcus were more predominant in either serum or mucosal samples. With the exception of the pneumococcus, we observed a progressive decline in serum IgG specific to all the infections above in the first six months of life. Pneumococcal IgG in serum exhibited a continuous rise in the first six months of life. <h4>Conclusions</h4> We successfully developed a synthetic peptide microarray and used it to profile the diversity of systemic and mucosal antibody against multiple infectious diseases in children. The data from the slide provide a snapshot overview of the breadth and kinetics of infectious disease antibodies early in life and opens the opportunity for conducting in-depth multi, multi-target serological studies of infectious diseases in future.