Two students are studying for an exam on the body’s defense systems. One of them insists that complement is part of the nonspecific second line of defense, but the partner insists that complement is part of an antibody immune response in the third line of defense. How would you explain to them that they are both correct?

Select the best answer or answers from the choices given: Cells that can directly attack target cells include all of the following except (a) macrophages, (b) cytotoxic T cells, (c) helper T cells, (d) natural killer cells.

Johnny has just been infected and needs your help in letting him know how his body is fighting the infection. To do so, describe how the innate and adaptive immune systems work together. You should address the following: 1. define adaptive and innate immunity; 2. Describe the role of natural killer cells (how do they work); 3. what are antigen presenting cells and what is their function, what are MHCs?; 4. describe the role of the complement system; 5. what is the role of interferons?; 6. How do helper T cells, cytotoxic T cells and B lymphocytes work make sure you address adaptive immunity memory?; 7. Define HIV, which cells do they attack and why do some individuals develop persistent lymphadenopathy (swollen or enlarged lymph nodes)?