Measurement of Shigella-specific antibodies in the first two years of life in Zambian children to refine correlates of protection and determine the optimal window for vaccination

Dr Roma Chilengi, Chief Scientific Officer
Centre for Infectious Disease Research in Zambia (Zambia)
Dr Joesph Campo 200x200px

Collaborators:
Professor Daniel Cohen, Tel Aviv University (Israel)
Professor Gad Frankel, Imperial College London (UK)

SUMMARY
Shigella is responsible for 190 million annual cases of diarrhoea in low and middle-income countries (LMIC), and estimated 65,000 deaths globally, or 11% of all diarrhoea related child deaths. Presently, no vaccine is available for prevention of Shigella infection but candidate vaccines are under advanced development. Unfortunately, there is insufficient knowledge on when infants in endemic areas get first infected, levels of Shigella-specific antibodies of maternal origin and acquired ones, and what would be the best time window for eventual vaccination. 

We propose to utilise existing serum samples from a cohort of Zambian infants recruited to study rotavirus vaccine response from 6 weeks through 24 months of age. We will screen samples collected at 6, 14, 52 & 104 weeks infants age by enzyme-linked immunosorbent assay (ELISA) for antibodies (IgG, IgA & IgM) to Shigella lipopolysaccharide (LPS) antigen. As antibody immune responses have been shown to be important for clinical protection, defining the time at which infants mount immune responses to Shigella in the absence of a vaccine will reveal the time when natural infection emerges and therefore, a potential optimal window for future vaccination.

Roma Chilengi at the Centre for Infectious Disease Research in Zambia has stored serum samples and clinical data on the cohort. Daniel Cohen at University of Tel Aviv has worked extensively on Shigella immunology, and will provide skills transfer to CIDRZ, the LMIC partner. Gad Frankel and team at Imperial College, London has been working on pathogen-host-microbiome interactions during infections with enteric pathogens employing a type III secretion system (T3SS) and on the role IgG antibodies play in protection. Findings from this preparatory work will result in a detailed understanding of the evolution of Shigella-induced immunity in infants naturally exposed to the infection and will be critical for future evaluation of vaccines under advanced clinical development.