Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

Viral vectors used in heterologous prime-boost regimens are one of very few vaccination approaches that have yielded significant protection against controlled human malaria infections. Recently, protection induced by chimpanzee adenovirus priming and modified vaccinia Ankara boosting using the ME-TRAP insert has been correlated with the induction of potent CD8(+) T cell responses. This regimen has progressed to field studies where efficacy against infection has now been reported. The same vectors have been used pre-clinically to identify preferred protective antigens for use in vaccines against the pre-erythrocytic, blood-stage and mosquito stages of malaria and this work is reviewed here for the first time. Such antigen screening has led to the prioritization of the PfRH5 blood-stage antigen, which showed efficacy against heterologous strain challenge in non-human primates, and vectors encoding this antigen are in clinical trials. This, along with the high transmission-blocking activity of some sexual-stage antigens, illustrates well the capacity of such vectors to induce high titre protective antibodies in addition to potent T cell responses. All of the protective responses induced by these vectors exceed the levels of the same immune responses induced by natural exposure supporting the view that, for subunit vaccines to achieve even partial efficacy in humans, "unnatural immunity" comprising immune responses of very high magnitude will need to be induced.

Original publication

DOI

10.1016/j.vaccine.2015.09.094

Type

Journal article

Journal

Vaccine

Publication Date

22/12/2015

Volume

33

Pages

7444 - 7451

Keywords

Clinical trials, Immunity, Malaria, Viral vectors, Adenoviruses, Human, Animals, Antibodies, Protozoan, Antigens, Protozoan, CD8-Positive T-Lymphocytes, Clinical Trials as Topic, Humans, Immunization, Secondary, Malaria Vaccines, Plasmodium falciparum, Protozoan Proteins, Vaccination, Vaccines, Subunit, Vaccinia virus