Cells that can directly attack target cells include all of the following excepta. macrophages,b. cytotoxic T cells,c. helper T cells,d. natural killer cells.

_______ is the immunoglobulin class that neutralizes viruses in the intestinal tract.

Which antibody class crosses the placenta from mother to child?

Your friend tests her snake-wrangling skills on an eastern diamondback rattlesnake, and is bitten and envenomated (injected with the snake's venom). In the emergency department, doctors administer the antivenin CroFab, which contains antibodies to the toxins in snake venom. Is this an example of active or passive immunity? Will this confer any lasting protection to your friend?