Immune responses to human papilloma viruses

Area of Science:

• Immunology
• Virology
• Oncology

Background:

• Human papillomavirus (HPV) infections are highly prevalent in sexually active individuals.
• Most HPV infections are cleared by the immune system, but some lead to benign lesions or cancer.
• Oncogenic HPV types can cause persistent infections, increasing the risk of cervical intraepithelial neoplasia (CIN3) and invasive carcinoma.

Purpose of the Study:

• To explore the role of cell-mediated immunity (CMI) in controlling HPV infections.
• To understand HPV's immune evasion strategies.
• To evaluate the efficacy of prophylactic HPV vaccines.

Main Methods:

• Histological analysis of lesion regression.
• Assessment of immune responses in immunocompromised individuals (e.g., HIV-infected).
• Review of animal models and clinical trial data for HPV vaccines.

Main Results:

• Regression of genital warts is associated with a Th1 response dominated by CD4+ T cells.
• Immunosuppression, such as in HIV infection, leads to increased HPV prevalence and high-grade squamous intraepithelial lesions (HGSIL).
• HPV employs immune evasion strategies, including downregulating interferon responses, delaying adaptive immunity activation.

Conclusions:

• CD4+ T cells play a central role in controlling HPV infection.
• Effective CMI is essential for clearing HPV and preventing disease progression.
• Prophylactic HPV L1 virus-like particle (VLP) vaccines are highly effective (>95%) in preventing HPV-associated benign and neoplastic diseases by generating neutralizing antibodies and circumventing viral immune evasion.