Both B and T cells are originally derived from cells of the:

A. Ceftaroline (Teflaro) is a fifth-generation cephalosporin antibiotic that is effective against MRSA (Methicillin-Resistant Staphylococcus Aureus). It's the first cephalosporin in its class with this capability, making it a valuable choice in treating MRSA infections.

B. Cefepime (Maxipime) is a fourth-generation cephalosporin that does not have specific activity against MRSA.

C. Ceftriaxone (Rocephin) is a third-generation cephalosporin, effective against a wide range of bacteria, but not specifically targeted at MRSA.

D. Cephalexin (Keflex) is a first-generation cephalosporin, primarily effective against Gram-positive bacteria, but not effective against MRSA.

A. Gut-associated lymphoid tissue (GALT): GALT is a component of the mucosa-associated lymphoid tissue (MALT) and refers to the immune cells found in the gastrointestinal tract. These cells play a significant role in local immune responses in the gut.

B. Bone marrow: The bone marrow is the primary site of blood cell production in the body. It contains stem cells that can differentiate into various blood cells, including B cells. B cells mature in the bone marrow.

C. Thymus: The thymus is an organ located near the heart and is crucial for the development of T cells. T cells mature in the thymus, where they learn to recognize self from non-self antigens.

D. Lymph nodes: Lymph nodes are small, bean-shaped structures that produce and store cells that help fight infection. While they are essential parts of the immune system, B and T cells are not originally derived from lymph nodes.