Suggested Answers for Insight Questions, Foundations in Microbiology, 7th Edition,
listed by chapter, number, and page location.
A note to the users of these answers: These answers discuss some of the possible ways to
approach the questions. They are not meant to be exhaustive in depth, but can offer information,
suggestions, and points of view that will be helpful in understanding some of the concepts
covered in the Insight and the chapter. Furthermore, they are not the final word--you may have
thought of some other explanations that are just as valid. It is hoped they will serve to stimulate
class discussion and inspire further research.
15.1, pg. 450 – Breast Feeding: The Gift of Antibodies
An antibody is a large protein molecule generally made up of 4 polypeptide strands linked
together. They are somewhat stable, but the molecules will ultimately break down or be
digested, which will cause them to lose function. There will be no way for the baby to get new
antibodies unless it makes its own actively or is given passive immunotherapy. One needs active
plasma cells to make antibody in the quantity necessary to control infectious agents.
15.2, pg. 465 – Monoclonal Antibodies: Variety Without Limit
If the antibody is derived totally from a mouse, then it will behave as an antigen in humans
because it is still a protein foreign to our immune systems. Some parts of antibodies have
epitopes unique to the animal that secretes them, so that even if the antibody works the same
way as ours does, it would stimulate our immune system to react against it. The reaction will
usually be an allergy or hypersensitivity, most likely something called immune complex disease
that causes antibody-antigen complexes to be deposited into tissues (Chapter16). By making
human-based monoclonal antibodies in mice, this potential for an adverse reaction is greatly
reduced.
15.3, pg. 470 – The Lively History of Active Immunization
The cross protection of vaccines doesn’t work for most microbes, but poxviruses are an
exception. This is true not only for vaccinia and variola but some other poxviruses such as
cowpox and monkeypox, both of which can also infect humans. The most likely explanation is
that the antigens or epitopes that emerge from the surface of these related viruses have the same
or a very similar shape. These epitopes are what stimulate the production of protective
antibodies. Thus, the antibodies formed against one type of virus would have a neutralizing effect
on the other types of viruses. One genetic explanation is that the genes that code for these
epitopes are highly conserved among the poxviruses, so do not vary greatly