We identified conserved molecules (enzymes, peptides, cytokines) that might play
a role in invertebrate innate immunity. We found these molecules by
immunoserological and immunohistochemical methods in association with
coelomocytes, leukocytes located in the coelomic cavity of the earthworm Eisenia
foetida. We detected the enzyme Cu-Zn-superoxide-dismutase (SOD), cytokines
(tumor necrosis factor-alpha, TNFalpha; transforming growth factor-alpha,
TGFalpha; and alpha peptide hormone, thyreotrope stimulating hormone, TSH) in
earthworm coelomocytes with monoclonal antibodies developed originally against
human and/or mouse antigens. Three coelomocyte subpopulations were identified
according to their form, size and granularity by microscopic and flow cytometric
analysis. These cell populations showed different reactivity with antibodies
against mammalian cell surface (CD) markers and different intracellular antigens.
Two coelomocyte types showed cell surface positivity with anti-Thy-1 (CD90), CD24
and TNF-alpha antibodies. Strong cytoplasmic reaction was shown with
anti-TNF-alpha and anti-SOD mAbs and a weaker but unambiguous reaction with
thyroid stimulating hormone (TSH) in two cell populations. The third population
was negative for all of the monoclonal antibodies. Our flow cytometric results
were confirmed by confocal microscopy both on the cell surfaces and
intracellularly.
