Biology · Immunology

Bacterial infections are generally divided into two broad classes: intracellular and extracellular bacterial infections. Consider the following properties related to bacterial infections: A. Humoral immune response is the main protective response against extracellular bacteria. B. Innate immunity is not effective against intracellular bacterial pathogens. C. Bacterial endotoxins do not induce an innate immune response. D. Intracellular bacterial infections generally induce a cell-mediated immune response resulting in secretion of cytokines which activate macrophages. Which one of the following combinations of statements is correct?