Antibodies are primarily effective against----?---- rather than?

a, viruses/pathogens b, bacteria/viruses c, viruses/bacteria d, pathogens/viruses e, none of the above

Antibodies are primarily effective against----?---- rather than?
b
Reply:b
Reply:The answer is B. You can eliminate answers that contain "pathogen" because a pathogen is anything that causes disease and thus, could be a virus or bacteria. Antibodies are more effective against bacteria rather than viruses for 2 main reasons: 1) Antibodies CAN bind to some viruses during the virus's extracellular phase (and thus, neutralize the virus and prevent it from infecting new cells). However, antibodies cannot enter cells. Most viruses cause disease upon cell entry. The only way to get rid of a virus infected cell is for that cell to be killed by an immune cell such as T cell, macrophage, or NK cell. Therefore, an antibody response is not the immune system's main line of defense against a virus. 2) Extracellular bacteria can easily be bound by antibody in the extracellular fluid. Antibody can a) neutralize the bacteria, preventing it from infecting cells; b) opsonize bacteria--the antibody coating on bacterial surfaces makes the bacteria easier to be phagocytosed ("eaten") and destroyed by phagocytic immune cells (such as macrophages) and c) antibody coating on bacterial surfaces can also activate the complement system (a system of plasma proteins) to lyse the bacteria, opsonize the bacteria, or to recruit more immune cells to the site of infection.
Reply:ridiculous question. Can a virus or a bacteria not be pathogenic?
Reply:ok an antibody is defined as a protein molecule made by the body's immune system that identifys and helps fight infections and other foreign substances in the body.





BACTERIA are single cell organism. SOME bacteria are capable of causing disease.





A VIRUS is a small particle that infects cells in biological organisms [many are pathogenic]. Viruses are intracellular parasites; can reproduce by invading and taking over the host cell.





A PATHOGEN is a disease causing organism.





Therefore, i think the answer is D, because we know that only some bacteria are capable of causing diseases.