- A A specific type of antibody secreted mainly by activated plasma cells residing within lymph nodes under usual circumstances according to most researchers
- B Signaling proteins that regulate immune cell communication and function: interleukins (IL-1, IL-2, IL-4), interferons, TNF, chemokines
- C Complement proteins that circulate freely and become activated by antigen-antibody complex formation over time in the majority of cases studied
- D Enzymes secreted by phagocytes that chemically digest engulfed antigens inside lysosomal compartments over time as widely reported
Correct answer: B. Signaling proteins that regulate immune cell communication and function: interleukins (IL-1, IL-2, IL-4), interferons, TNF, chemokines
Explanation: Cytokines are small signaling proteins that mediate cell-to-cell communication in immunity. Interleukins (IL-2 stimulates T cell proliferation; IL-4 promotes B cell differentiation to IgE). Interferons (antiviral), TNF-alpha (inflammation), chemokines (direct cell migration).
Concept context
Innate and adaptive immunity, B cells, T cells, antibodies, vaccines, and immune disorders. Critical for NEET.