Cross-Clade Recognition of HIV-1 CAp24 by CD4+ T Cells in HIV-1-Infected Individuals in Burkina Faso and Germany

Thomas Böhler*, 1, Vanessa Mrosek1, Kerstin Müller1, §, Paul Schnitzler1, Martin Hartmann2, Thierry Ouedraogo3, Boubacar Coulibaly3, Ali Sié3, Vanda Bartonova1, Denis M Tebit1, #, Hans-Georg Kräusslich1
1 Department of Virology, and
2 Department of Dermatology, University of Heidelberg, Germany
3 Nouna Health Research Center, Nouna, Burkina Faso

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© Böhler et al.; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License( which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the Department of Virology, University of Heidelberg, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany; Tel: +49-6221 565002; Fax: +49-6221 565003; E-mail:
§ Present address: Bernhard-Nocht Institute of Tropical Medicine, Hamburg, Germany
# Present address: Division of Infectious Diseases, Case Western Reserve University, Cleveland (OH), USA


The presence of antigen-specific cellular immune responses may be an indicator of long-term asymptomatic HIV-1-disease. The detection of cellular immune responses to infection with different subtypes of HIV-1 may be hampered by genetic differences of immunodominant antigens such as the capsid protein CAp24. In Nouna, Burkina Faso, HIV-1 circulating recombinant forms CRF02_AG and CRF06_cpx are the 2 major strains detectable in HIV-1-infected individuals, while subtype B strains prevail in Europe and North America. Amino acid sequences of CAp24 were assessed in blood samples from 10 HIV-1-infected patients in Nouna, Burkina Faso. Production of interferon-gamma (IFN-γ) in peripheral blood CD4+ lymphocytes in response to recombinant HIV-1 proteins derived from clade B (including CAp24NL4-3) was measured using a modified flow-cytometry-based whole blood short term activation assay (FASTimmune, BDBiosciences). IFN-γ production following stimulation with a whole length CAp24 protein derived from clade B (CAp24NL4-3) was additionally quantified in comparison to a CAp24 protein derived from CRF02_AG (CAp24BD6-15) in 16 HIV-1-infected patients in Heidelberg, Germany. Amino acid sequence identity of CAp24 obtained from patients in Nouna ranged between 86 and 89% when compared to the clade B CAp24NL4-3 consensus sequence, between 90 and 95% when compared to the circulating recombinant form CRF06_CPX consensus sequence, and between 92 and 96% when compared to the CAp24BD6-15 consensus sequence. Significant numbers of HIV-1-specific CD4+ lymphocytes producing IFN-γ were detected in 4 of 10 HIV-1-infected patients. In 7 of 16 patients in Heidelberg, recombinant CAp24BD6-15 stimulated IFN-γ-production in CD4+ lymphocytes to a similar extent as the clade B-derived CAp24NL4-3. Thus, antigen-specific CD4+ lymphocytes from both West African and European patients infected with different strains of HIV-1 show relevant cross-clade recognition of HIV-1 CAp24 in a flow-cytometry-based whole blood short term activation assay.