By Caleb Sooknanan ’20

Tuberculosis (TB) is the world’s most prominent cause of death by infection. Scientists have become increasingly interested in the humoral immune responses associated with TB, but it is difficult to find the antigenic targets that correspond to specific stages of TB infection and disease. Dr. Davide Valentini and researchers at Karolinska Institutet conducted a study to determine whether peptide microarray platforms could be used to find epitopes of immunogenic TB antigens.

To conduct this study, the researchers measured serum antibody responses of patients with pulmonary TB from Africa and South America, two regions with high TB incidence. The responses were then analyzed using a peptide array platform, which involved the epitope mining of linear peptides from Mycobacterium tuberculosis antigens placed on miniature slides. The microarray spanned 154 proteins of M. tuberculosis and was used to yield specific Immunoglobulin G (IgG) antibody responses. Recognizing specific M. tuberculosis epitopes in patients with and without active TB, the researchers used a humoral immune response landscape to explain trends among patients.

The IgG response patterns of TB patients were different from those of healthy individuals, with each antigen’s molecular complexity affecting the strength of recognition. Also, South American individuals with or without TB displayed a stronger serum IgG response to the M. tuberculosis antigens than that of African individuals.

Through this study, the researchers were able to recognize immune response landscapes as new mediums for understanding the recognition of antigenic peptides by antibodies. They concluded that peptide microarray platforms could be more cost-effective and accessible than current diagnostic tools. The results may help scientists designate more effective vaccine targets and therapeutic tools to address TB in patients.

References:

1. Valentini, et al., Immune recognition surface construction of Mycobacterium tuberculosis epitope-specific antibody responses in tuberculosis patients identified by peptide microarrays. International Journal of Infectious Diseases 56, 155-166 (2017). doi: 10.1016/j.ijid.2017.01.015

Image retrieved from: http://www.popsci.com/sites/popsci.com/files/styles/large_1x_/public/public/screen_shot_2015-02-06_at_9.34.28_am.png?itok=qJuit5Pm