Abstract
Thirty different genes including cytokines, chemokines, granzymes, perforin and specifically integrins were evaluated in Peyer's patch-KdGag197–205-specific CD8+ T cells (pools of 100 cells) using Fluidigm 48.48 Dynamic arrays following three different prime-boost immunization strategies. Data revealed that the route of prime or the booster immunization differentially influenced the integrin expression profile on gut KdGag197–205-specific CD8+ T cells. Specifically, elevated numbers of integrin αE and αD expressing gut KdGag197–205-specific CD8+ T cells were detected following mucosal but not systemic priming. Also, αE/β7 and αD/β2 heterodimerization were more noticeable in an intranasal (i.n.)/i.n. vaccination setting compared to i.n./intramuscular (i.m) or i.m./i.m. vaccinations. Moreover, in all vaccine groups tested α4 appeared to heterodimerize more closely with β7 then β1. Also MIP-1β, RANTES, CCR5, perforin and integrin α4 bio-markers were significantly elevated in i.n./i.m. and i.m./i.m. immunization groups compared to purely mucosal i.n./i.n. delivery. Furthermore, when wild type (WT) BALB/c and IL-13 knockout (KO) mice were immunized using i.n./i.m. strategy, MIP-1α, MIP-1β, RANTES, integrins α4, β1 and β7 mRNA expression levels were found to be significantly different, in mucosal verses systemic KdGag197–205-specific CD8+ T cells. Interestingly, the numbers of gut KdGag197–205-specific CD8+ T cells expressing gut-homing markers α4β7 and CCR9 protein were also significantly elevated in IL-13 KO compared to WT control. Collectively, our findings further corroborate that the route of vaccine delivery, tissue microenvironment and IL-13 depleted cytokine milieu can significantly alter the antigen-specific CD8+ T cell gene expression profiles and in turn modulate their functional avidities as well as homing capabilities.
Highlights
It is well established that route of vaccine delivery can greatly influence the quality of HIV-specific CD8+ T cell immunity
wild type (WT) BALB/c (n = 4–5) were primed with FPV-HIV and boosted with VV-HIV vaccine using i.n./i.n., i.n./i.m. or i.m./i.m. vaccine regimes as indicated in methods, fourteen days post booster immunization gut KdGag197–205-specific CD8+ T cell were sorted in groups of hundred cells and mRNA expression profiles of 30 genes of interest (Table 1) were evaluated using Fluidigm 48.48 Dynamic arrays
When expression of cytokines IFN-γ, TNF-α, IL-2, IL-4, IL-13 and IL-17 mRNA by gut KdGag197–205-specific CD8+ T cells were evaluated, no IFN-γ, IL-2, IL-4, IL-13 and IL-17 mRNA were detected, majority of the pools of hundred gut KdGag197–205-specific CD8+ T cells obtained from the three immunization regimes (i.n./i.n.- 9 out of 9; i.n./i.m. and i.m./i.m.- 8 out of 10, i.e. 80–100%) expressed TNF-α, and the expression profile between the three regimes were very similar (Fig 1a)
Summary
It is well established that route of vaccine delivery can greatly influence the quality of HIV-specific CD8+ T cell immunity. Studies where i.m. pDNA-HIV/ i.n FPV-HIV; i.n. FPV-HIV/ i.m. attenuated vaccinia virus (VV)-HIV and i.n. VV-HIV/ i.m. FPV-HIV were evaluated, i.n. FPV-HIV prime followed by i.m. VV-HIV booster vaccination has shown to induce robust polyfunctional HIV-specific T cell immunity compared to the two other prime-boost vaccination strategies [6]. We have shown that compared to purely systemic (i.m FPV-HIV/ i.m VV-HIV) immunization regime, i.n. FPV-HIV prime followed by i.m VV-HIV booster immunization strategy induce robust long lasting CD8+ systemic and mucosal T cell responses to HIV-1 vaccine antigens [9], which were of higher avidity [10, 11]. Purely mucosal immunization i.n./i.n. or combined mucosal systemic i.n./i.m immunization induced HIV-specific CD8+ T cells with lower IL-4 and IL-13 expression compared to systemic immunization (i.m./i.m.), which were of higher avidity. Later studies using IL-13 KO mice have confirmed that IL-13 can significantly dampen the induction of effector and memory CD8+ T cells of higher avidity following vaccination [10, 12]
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