Which helper T cell subset secretes the cytokines that drive B cells to become antibody-secreting plasma cells?

1. Helper T cells bear the CD4 molecule and are told apart by the characteristic set of cytokines they secrete rather than by surface markers. 2. Th1 cells secrete cytokines that regulate the activity and development of macrophages and other types of T cells. 3. Th2 cells act on B cells to drive their differentiation into plasma cells that make antibody. 4. T cell help is required for antibody responses to most protein antigens, which is why such antigens are called T cell-dependent. 5. Regulatory T cells suppress other T cell responses instead of helping B cells, and cytotoxic T cells kill infected targets. _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_