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Updated: May 13, 2026

Measuring Endoplasmic Reticulum Stress and Unfolded Protein Response in HIV-1 Infected T-Cells and Analyzing its Role in HIV-1 Replication
Published on: June 14, 2024
Endoplasmic reticulum aminopeptidase 2 haplotypes play a role in modulating susceptibility to HIV infection
Mara Biasin1, Manuela Sironi, Irma Saulle
1Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy. mara.biasin@unimi.it
Objective:
Haplotype-specific alternative splicing of the endoplasmic reticulum (ER) aminopeptidase type 2 (ERAP2) gene results in either full-length (FL, haplotype A) or alternatively spliced (AS, haplotype B) mRNA. As ERAP2 trims peptides loaded on major histocompatibility complex (MHC) class I and CD8 T lymphocytes protect against viral infections, we analysed its role in resistance to HIV-1 infection.
Methods:
ERAP2 polymorphisms were genotyped using a TaqMan probe, and human leukocyte antigen (HLA) typing of class-I HLAB locus was performed by single specific primers-polymerase chain reaction method. To verify whether ERAP2 genotype influences susceptibility to HIV-1 infection in vitro we performed HIV-1 infection assay. We evaluated antigen presentation pathway with PCR array and the viral antigen p24 with ELISA.
Results:
Genotype analysis in 104 HIV-1-exposed seronegative individuals (HESNs) exposed to HIV through IDU-HESN and 130 controls from Spain indicated that hapA protects from HIV infection. Meta-analysis with an Italian cohort of sexually exposed HESN yielded a P value of 7.6 × 10. HLAB typing indicated that the HLA-B*57 allele is significantly more common than expected among HESN homozygous for haplotype A (homoA). Data obtained in a cohort of 139 healthy Italian controls showed that following in-vitro HIV-1 infection the expression of ERAP2-FL and a number of genes involved in antigen presentation as well as of MHC class I on the surface of CD45 cells was significantly increased in homoA cells; notably, homoA peripheral blood mononuclear cells, but not isolated CD4 cells, were less susceptible to HIV-1 infection.
Conclusion:
ERAP2 hapA is correlated with resistance to HIV-1 infection, possibly secondarily to its effect on antigen processing and presentation.
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