Case Studies Chapter 4 # 3 & 4

Caitlin Kilcullen, Lauren Lit, Kelly Scheer, Josh Matthews, Geena Tomasetti, Alyssa Dilella

Dendritic Cells

Dendritic cells function as antigen presenting cells (APC). In fact, the dendritic cells are more efficient apcs than macrophages. It is believed that they capture antigen or bring it to the lymphoid organs where an immune response is initiated. Dendritic cells bind high amount of HIV, and may be a reservoir of virus that is transmitted to CD4+ T cells during an activation event.

Helper T Cells Helper T Cells or CD4+ cells are activated by dendritic cells. When dendritic cells sense that a material is dangerous, they stimulate the helper t cells.

CD4+ refers to a surface protein on this class of T cells.

Helper T cells can stimulate another group of white blood cells called B cells to produce antibodies that bind that specific antigen and immobilize it, preventing it from causing infection.

Cytotoxic T Cells

Pathogens that escape antibody detection can enter and infect cells. The surface of infected cells changes, and this change is recognized by T cells. Cytotoxic T cells kill infected cells, preventing these cells from producing more pathogen. Cytotoxic T cells must interact with Helper T cells to regulate destruction of infected cells.

HIV and the role of Helper T Cells

HIV can attach to helper t cells on the outer protein membrane. (Envelope Protein)

HIV attacks helper t cells. With fewer helper t cells, the immune system cannot signal B cells to produce antibodies or Cytotoxic T cells to kill infected cells.

When all the helper t cells are destroyed in a body, HIV becomes AIDS.

Acquired Immune Response

An acquired Immune Response is immunity that develops with exposure to various antigens. Your immune system builds a defense that is specific to that antigen.

Vaccinations are an example of an acquired immune response because they are telling your body to produce antibodies against a specific disease, therefore protecting you from contracting the disease.

Vaccination

There isn’t a vaccine for the common cold or HIV because there are several different viruses that can cause the common cold and HIV. These viruses mutate so quickly that it is difficult to make a traditional vaccine for them.