What enhances the multiplication of T cells in culture -
T cells undergo blast transformation (multiplication) on treatment with mitogens such as : - 

       - Phytohemagglutinin (PHA)
       - Concanavalin A (Con A)
       - Anti CD-3

B Cells undergo a similar transformation with : -

      - Bacterial endotoxins
      - Staphylococcus aureus
      - EB virus
      - Anti Ig
Remember :
Mature B and T cells before they encounter antigen are called naive cells.
Phytohemagglutinin
Chemotactic factor
Leukotrienes
Prostaglandins