global-vaccines-2017-posters-accepted-abstracts

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Ann Clin Trials Vaccines Res. 2017 | Volume 1 Issue 2

Global Vaccines & Vaccination Summit & B2B

November 01-02, 2017 | Toronto, Canada

Introduction:

The membrane proximal external region (MPER)

of HIV-1 envelope glycoprotein-41 (gp41) is targeted by several

broadly neutralizing antibodies whose conserved linear

epitopes are promising targets for vaccine design. However, a

formidable challenge has remained the difficulty to design and

deliver MPER based immunogens for the efficient induction of

such broadly neutralizing HIV-1 specific antibodies (bnAb). This

is mainly because the linear bnAb MPER epitopes are poorly

accessible to the immune system. The overall objective of this

study therefore was the development and validation of an

RNA coliphage Qβ display system for efficient presentation of

conserved bnAb epitopes to the immune system

Method:

To overcome the challenge of effective presentation

of MPER to the immune system we have selectively engineered

the surface of the RNA coliphage Qβ to to display 12 molecules

of MPER per phage particle. The expression cassettes were

used for the production of QβMPER recombinant hybrid phages

after transformation of E. coli HB101 strain.

Results:

Specific recognition of all the linear MPER based bnAb

epitopes were confirmed in ELISA with QβMPER VLP as antigen

and the bnAb 2F5, Z13, 4E10 and 10E8 as antibodies. Next

the prevalence of MPER specific antibodies was determined

in plasma from antiretroviral naïve HIV infected participants

of the CIRCB AFRODEC cohort. The greater majority (84%) of

participants’ plasma showed MPER peptide specific reactivity

with antibody titers ranging from 200 to 409600 comparative

to background values with Qβ empty as antigen.

Conclusion:

Thus, this novel QβMPER VLP can be used to

monitor MPER- specific immune responses in clinical samples.

In addition the QβMPER VLP can be used as immunogens either

alone or in combination with other strategies for the induction

of MPER specific immunity against HIV-1.

Targeting conserved broadly neutralizing epitopes within HIV-1 envelope gp41 MPER as vaccine

immunogens for seronegative partners of HIV-1 discordant couples

Godwin W Nchinda

Laboratory of Vaccinology/Biobanking, Cameroon