Which three cell types express MHC class II and act as professional antigen-presenting cells?

1. Many cell types express class I MHC molecules for the presentation of intracellular antigens, which stimulates a cytotoxic T cell response. 2. Class II MHC molecules are expressed only on cells of the immune system that affect other arms of the immune response. 3. Those cells are called professional antigen-presenting cells, and they are macrophages, dendritic cells and B cells. 4. Macrophages stimulate T cells to release cytokines that enhance phagocytosis, dendritic cells bring antigens to regional draining lymph nodes, and B cells present antigen for certain antibody responses. 5. Natural killer cells kill infected targets and neutrophils phagocytose them, but class II sits on neither, so any option naming them fails. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 21 "The Lymphatic and Immune System", section 21.3 The Adaptive Immune Response: T lymphocytes and Their Functional Types_