Malignant tumors are classified by their embryonic

tissue of origin:

Carcinomas -derive from epithelia such as endoderm

(gut epithelium) or ectoderm (skin and neural epithelia) 

Sarcomas - derive from mesoderm (muscle, blood, and

connective tissue precursors)

TLS Online TPP Program

#Id: 1642

#Unit 4. Cell Communication and Cell Signaling

Bare lymphocyte syndrome- Defects in class II MHC transcriptional activator called CIITA.

TLS Online TPP Program

#Id: 1643

#Unit 4. Cell Communication and Cell Signaling

Class II, presentation is inhibited by treatment of the cells with an agent that blocks endocytic processing within the cell (chloroquine).

TLS Online TPP Program

#Id: 1644

#Unit 4. Cell Communication and Cell Signaling

Inhibition of class I presentation observed when protein synthesis was blocked by the inhibitor emetine.

TLS Online TPP Program

#Id: 1645

#Unit 4. Cell Communication and Cell Signaling

Presentation of nonpeptide (lipid and lipid-linked) antigens derived from pathogens involves the nonclassical class I–like CD1 molecule.

TLS Online TPP Program

#Id: 1646

#Unit 4. Cell Communication and Cell Signaling

Antibodies serve as physiological bridges between an antigen present on a pathogen, and the cells or molecules that will ultimately destroy it.

TLS Online TPP Program

#Id: 1647

#Unit 4. Cell Communication and Cell Signaling

Heavy chain contain more constant region in compare to variable region, in contrast in the light chain variable and constant region are equal.