Biology · Immunology

An antigen was injected into a mouse. Macrophages and antigen-primed T H cells were isolated from this mouse to perform the following in vitro experiments: A. Macrophages were treated with the antigen for an hour and then incubated with T H cells. B. Macrophages were treated with paraformaldehyde first and then treated with the antigen for an hour. These macrophages were then incubated with T H cells. C. Macrophages were treated with paraformaldehyde first, then treated with the digested (proteolytically cleaved) antigen for an hour. These macrophages were then incubated with T H cells. D. Macrophages were treated with the antigen for an hour and then treated with paraformaldehyde. These macrophages were then incubated with T H cells. Which of the above experiments would lead to T H cell proliferation?