antibacterial mechanisms of neutrophils (3)
Fc receptors (FcR) on the surface of neutrophils, macrophages and other immune cells recognize which of the following?
- Macrophages that have encountered an antigen
- Complement molecules on a pathogen
- Pathogen-associated molecular patterns
- Antibodies that have coated antigens
- Antigens on pathogens
Antibodies that have coated antigens om the surface of pathogens
Describe a dendritic cell
A phagocytic antigen-presenting cell. Expresses MHC class II and Fc receptors. Inhibited by interleukin-10.
The cell that links the innate and adaptive immunity is the __________cell
dendritic
B cells mediate within humoral/cellular immunity wherease T cells mediate within humoral/cellular immunity
- B cells –> humoral (mn: B for Blood and antiBodies)
- T cells –> Cellular (mn: T for touchy touch
diff between antibody versus immunoglobulin
Immunoglobulins are attached to the B cell membrane via transmembrane domain while antibodies float in the circulation.
*alternate sources say the words can be used interchangeably
MHC I vs MHC II
MHC I molecules are expressed on all nucleated cells and are essential for presentation of normal “self” antigens. Cells that become infected by intracellular pathogens can present foreign antigens on MHC I as well, marking the infected cell for destruction.
MHC II molecules are expressed only on the surface of antigen-presenting cells (macrophages, dendritic cells, and B cells). Antigen presentation with MHC II is essential for the activation of T cells.
B cell antigen receptor (BCR) are also called
immunoglobulins
TCRs are heterodimers/homodimers? predominately made of
alpha and beta (95%) dimers,
5% are γ and delta 𝛿 (mostly present in mucosal surface as intraepithelial lymphocytes, providing protection of mucosal surface; they recognize antigens without MHC presentation)
NK cells are predominately involved in lysing what type of cells
tumor cells, virus infected cells.
Immature B cells undergo negative selection, also called clonal deletion, which does what?
removes B cells that bind with self-antigen
Two key signals are involved in B cell and T cell interaction and activate B cells, what are they?
- MHC recognition by the T cell, and is necessary for the second signal.
- The B cell displays the antigen-MHC II complex, and that it is recognized by the T-cell receptor (TCR) and CD4 proteins of the Helper T cell.
- The second signal involves co-stimulation by B and T cell proteins:
- Binding of B7-2 with CD-28 triggers cytokine activation.
- Binding of CD40 with CD40L (L is for ligand) triggers class switching and affinity maturation.
- Cytokines released by the Helper T cell influence class switching from IgM/IgD to the other isotypes (IgA, IgG, and IgE).
What factors are involved in the phospholipase C cell signaling pathway
Kinesins vs dyneins
Kinesins and dyneins have similarities, but an important difference is that most kinesins travel toward the plus end of the microtubule that they are on (i.e., away from the center of the cell), while dyneins travel toward the minus end of the microtubule (towards the center of the cell).
Type II collagen is located in
Car-TWO-lage
vitreous humor
nucleus pulposus
Type I Collagen
found in many tissues besides cartilage,
where Type II collagen is found
dynein vs Kinesin
Microtubules can also serve as a substrate along which dynein and kinesin can move. This process requires hydrolysis of ATP.
- Dynein moves retrograde: the “minus” end of the microtubule
- Kinesin moves anterograde: the “plus” end of the microtubule, where new subunits are added
Mnemonics: “Dyne-in or taKe out?” Also, the “K” of kinesin looks like a “+” → kinesin moves to the “plus” end.
What features of the small intestines make them
a favorable place for drug absorption?
high surface area because of villi
long residence time
low pH (but not too low)
highly vascularized
What features of the stomach makes it an
unfavorable place for drug absorption?
pH sis very low
mucous membranes
short residence time
thick wall
