Se analizo la actividad antibacteriana del suero de 23 cocodrilianos vivientes. However, despite living in environments rich in potentially pathogenic micro organisms, these wounds often heal without infection. Several species of crocodylians have been shown to be resistant to disease. For instance, Madsen et al. (1998) found a variety of Salmonella serotypes in the cloacae of healthy Nile crocodiles (Crocodylus niloticus). Manolis et al. (1991) found a high incidence of Salmonella in farmed Crocodylus johnsoni and Crocodylus porosus, while Scott and Foster (1997) described the isolation of Salmonellae from both farmed and wild American alligators (Alligator mississippiensis). In addition, Williams et al. (1990) found 23 different species of bacteria in the gular and paracloacal glands of healthy American alligators.

En el sistema complemento de los reptiles requiere metales divalentes, temperaturas de 5 y 40 grados, superiores e inferiores lo inactivan . In a subsequent study, Merchant and Britton (Merchant and Britton, 2006) found that the lysis of sheep red blood cells by serum from saltwater (Crocodylus porosus) and freshwater (Crocodylus johnstoni) crocodiles required divalent metal ions, was heat sensitive and was unaffected by methylamine; therefore, suggesting that the alternative pathway was responsible for the lysis. Despite reptiles’ key place in evolutionary history, reptilian immune responses have received relatively little attention. Like all jawed vertebrates, reptiles possess both an innate and adaptive immune system. The innate system, which includes components such as non-specific leukocytes, antimicrobial peptides and the complement system, responds quickly as a non-specific first line of defense against a broad range of pathogens. In many cases the responses are stronger than those of mammals. Much less is known about the adaptive branch, and studies of the cell-mediated and humoral responses have been generally hampered by a lack of appropriate reagents.

moleculas del sistema inmune en tortugas: Lisozymas con actividad antibacteriana y otrs moleculas son catelicidinas con actividad antifungica yactividad antibacteriana, incluso mas potente que farmacos ampicilina y bencilpenicilina. En el cocodrilo siames se aislo una pequeña proteina cationica 2008). A small cationic protein was isolated from the Siamese crocodile (Crocodylus siamensis), which demonstrated antibacterial activity against S. typhi, E. coli, S. aureus, Staphylococcus epidermidis, K. pneumoniae, P. aeruginosa and Vibrio chorelae (Preecharram et al., 2008). These antimicrobial peptides offer potent protection for reptiles against infection as well as provide exciting opportunities in the search for new clinical or agricultural antibiotics.

Las defensinas son: proteins that have a characteristic -sheet-rich fold as well as six disulphide-linked cysteines and have been found in all mammals that have been examined as well as in birds

Se han descrito defensinas con actividad antibacteriana against Escherichia coli and Salmonella typhimurium as well as antiviral activity against the Chandipura virus (Chattopadhyay et al., 2006). The first - defensin from reptilian leukocytes was recently isolated from the European pond turtle Emys orbicularis. Known as TBD-1, the peptide demonstrated strong activity against E. coli, Listeria monocytogenes, Candida albicans and methicillin-resistant Staphylococcus aureus (Stegemann, 2009).

El timo y el bazo se mantienen activos durante el verano e involucionan en en invierno cuando se encuentran en hibernación

Reptiles are the only ectothermic amniotes, and therefore become a pivotal group to study in order to provide important insights into both the evolution of the immune system as well as the functioning of the immune system in an ecological setting.