Selective Apc-Targeting of a Novel Fc-Fusion Multi-Immunodominant Recombinant Protein (Ttax-Tenv:Mfcγ2a) for Htlv-1 Vaccine Development Publisher Pubmed



Shafifar M¹ ; Mozhgani SH^{2, 3} ; Razavi Pashabayg K¹ ; Mosavat A⁴ ; Karbalaei M⁵ ; Norouzi M^{1, 6} ; Rezaee SA⁷ Show Affiliations
Source: Life Sciences Published:2022

Abstract

Aims: HTLV-1 causes two life-threatening diseases: adult T-cell leukaemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis. Due to the lack of proper treatment, an effective HTLV-1 vaccine is urgently needed. Main methods: DNA sequences of 11–19 and 178–186 amino acids of HTLV-1-Tax and SP2 and P21 were fused to the mouse-Fcγ2a, or His-tag called tTax-tEnv:mFcγ2a and tTax-tEnv:His, respectively. These constructs were produced in Pichia pastoris, and their immunogenicity and protective properties were assessed in a mouse challenging model with an HTLV-1-MT2 cell line. Key findings: The immunogenicity assessments showed significant increase in IFN-γ production in animals receiving tTax-tEnv:mFcγ2a (1537.2 ± 292.83 pg/mL) compared to tTax-tEnv:His (120.28 ± 23.9, p = 0.02). IL-12 production also increased in group receiving tTax-tEnv:mFcγ2a than tTax-tEnv:His group, (23 ± 2.6 vs 1.5 ± 0.6, p = 0.01), respectively. The IFN-γ and IL-12 levels in the Fc-immunised group were negatively correlated with PVL (R = -0.82, p < 0.04) and (R = -0.87, p = 0.05), respectively. While, IL-4 was increased by tTax-tEnv:His (21.16 ± 1.76 pg/mL) compared to tTax-tEnv:mFcγ2a (13.7 ± 1.49, p = 0.019) with a negative significant correlation to PVL (R = -0.95, p = 0.001). Significance: The mouse challenging assay with tTax-tEnv:mFcγ2a showed 50 % complete protection and a 50 % low level of HTLV-1-PVL compared to the positive control receiving HTLV-1-MT2 (p = 0.001). Challenging experiments for the His-tag protein showed the same outcome (p = 0.002) but by different mechanisms. The Fc-fusion construct induced more robust Th1, and His-tag protein shifted more to Th2 immune responses. Therefore, inducing both T helper responses, but a Th1/Th2 balance in favour of Th1 might be necessary for appropriate protection against HTLV-1 infection, spreading via cell-to-cell contact manner. © 2022 Elsevier Inc.