Natural bioactive polysaccharides have been investigated for their ability to modulate antiviral immune responses. Polysaccharide peptide (PSP) from Coriolus versicolor previously restricted human immunodeficiency virus type 1 (HIV-1) entry into monocytic cells through a protein kinase R (PKR)-dependent cytoskeletal mechanism. However, its impact on antiviral signaling in adaptive cluster of differentiation 4 (CD4)+ T-cell models remains incompletely defined. Here, we evaluated concentration- and time-dependent effects of PSP (50–1000 µg/mL) in Jurkat T cells over 3 and 6 days. Cell viability was assessed by MTT, trypan blue exclusion, and viable cell density analysis. Immunoblotting and reverse transcription quantitative polymerase chain reaction (RT-qPCR) were performed to examine Toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB), signal transducer and activator of transcription 1 and 2 (STAT1/STAT2), PKR, interferon gamma (IFN-γ), and cofilin-1 signaling. PSP did not induce cytotoxicity at any concentration. Instead, PSP promoted dose- and time-dependent upregulation of intracellular TLR4, PKR, phospho-PKR (Thr446), Cofilin-1, phospho-Cofilin-1 (Ser3), phospho-STAT1 (Tyr701), phospho-STAT2 (Tyr690), phospho-NF-κB (Ser536), and IFN-γ, with amplified responses at Day 6. These changes were paralleled by transcriptional induction of antiviral-associated genes. Collectively, PSP induces coordinated interferon (IFN)-associated and cytoskeletal regulatory signaling in Jurkat T cells without cytotoxicity, providing a mechanistic framework for future evaluation of viral permissiveness and antiviral responses in adaptive immune models.
Rosario-Sanfiorenzo et al. (Mon,) studied this question.