Characterization of Serum Complement Activity in Three Species of Crocodilians from Southeast Mexico.
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Date
2014-07
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Abstract
To characterize the serum complement innate immune system in three species of
crocodilians native to southeast Mexico.
Methodology: Plasma collected from three wild crocodilian species native to southeast
Mexico were exposed to sheep red blood cells (SRBCs) to measure hemolysis, which is
used as an indication of serum complement immune activity.
Results: Incubation of different volumes of plasma from Crocodylus acutus, Crocodylus
moreletii, and Caiman crocodilus resulted in a volume-dependent increase in SRBC
hemolysis. However, while maximum hemolysis for C. acutus and C. moreletii were both
approximately five-fold higher than that of Ca. crocodilus. A kinetic study revealed that the
hemolysis was rapid, with near-maximum activity recorded at 30 min for C. acutus and C.
moreletii. However, Ca. crocodilus activity exhibited a significant increase (P<.5) only
between one and two hours. A thermal analysis showed that the SRBC hemolysis was
maximal at temperatures to which these species thermoregulate. The thermal profiles
were similar for all three species, although the activity was lower for Ca. crocodilus (P<.01). The SRBC hemolysis was strongly inhibited by mild heat treatment (56°C,30 min)
and also by EDTA, indicating that the hemolytic activity was probably due to the presence
of crocodilian serum complement activity. The EDTA-inhibited activity was restored by the
addition, of a 20mM excess of Ca2+or Mg2+, but not Fe2+orCu2+, thus exhibiting the specific
need for Ca2+orMg2+.
Conclusions: The serum complement activities of C. acutus and C. moreletii are much
higher (P<.01) than Ca. crocodilus, which may be related to the maximum sizes and
increased aggressive natures of C. acutus and C. moreletii.
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Keywords
American crocodile, spectacled caiman, morelet’s crocodile, serum complement, innate immunity, crocodilian, sheep red blood cells, Crocodylus acutus, Crocodylus moreletii, Caiman crocodiles
Citation
Merchant Mark, Falconi Rodolfo, LeFleur Leah, Trahan Cassandra, LeDoux Shea, Escobedo Armando. Characterization of Serum Complement Activity in Three Species of Crocodilians from Southeast Mexico. International Journal of Biochemistry Research & Review 2014 Jul-Aug ; 4 (4) : 295-305.