Immunology & Practice Test 2026 | Exam Prep

A patient presents with recurrent bacterial infections, particularly of the respiratory tract, and a deficiency in the complement component C3. Which of the following immunological mechanisms would be most severely impaired, leading to this susceptibility?

During an immune response to a novel intracellular pathogen, a dendritic cell (DC) presents antigen to a naive T cell. The DC also upregulates co-stimulatory molecules like CD80 and CD86. Which of the following cytokines, released by the DC in the context of PAMP recognition via TLRs, would be most critical for promoting the differentiation of this naive T cell into a Th1 cell, thereby facilitating a robust cellular immune response?

A patient with a genetic defect exhibits a complete absence of functional MHC class I molecules on their cells. Which of the following immune cell populations would be severely impaired in its ability to recognize and eliminate virally infected cells or tumor cells?