A) An antibody is specifically produced in response to an antigen.
B) An antibody is produced by T cells and an antigen is a foreign protein.
C) An antigen is presented by antigen presenting cells to plasma cells, which produce antibodies.
D) An antigen is a disease-causing organism, and antibodies are produced by B cells.
E) An antibody generally induces antigen formation.

A) Prolonged infections
B) Cigarette smoking
C) Gum disease
D) Obesity
E) Vitamin D deficiency

A) They are features of pathogens recognized by animal cells.
B) They trigger activation of phagocytes.
C) They react with specific receptors on host cells.
D) They are found on all microbes except viruses.
E) The peptidoglycan of gram-positive bacteria is an example.