Bacterial Antigens
Bacterial cells are between 0.3 and 5 lm in size. They have three basic forms: cocci, straight rods, and curved or spiral rods.
Virulent bacteria cause disease through the elaboration of factors that facilitate adherence, persistence, invasion, and toxigenicity. Genes that encode virulence factors may be carried on mobile genetic elements such as plasmids or bacteriophages or are found on large pathogenicity islands on bacterial chromosomes. http://www.creative-diagnostics.com/Bacterial-Antigens.htm