Open AccessAn immunohistochemical analysis of onchocercal nodules: evidence for an interaction between macrophage MRP8/MRP14 and adult Onchocerca volvulus
Author(s) -
EDGEWORTH J. D.,
ABIOSE A.,
JONES B. R.
Publication year - 1993
Publication title -
clinical & experimental immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.329
H-Index - 135
eISSN - 1365-2249
pISSN - 0009-9104
DOI - 10.1111/j.1365-2249.1993.tb05952.x
Subject(s) - onchocerca volvulus , biology , cd68 , onchocerciasis , pathology , macrophage , ivermectin , immunology , cd11c , immunohistochemistry , phenotype , medicine , in vitro , zoology , biochemistry , gene
SUMMARY We have used a panel of MoAbs to investigate the phenotype of macrophages and other leucocytes infiltrating onchocercal nodules. Nodules were removed from individuals at the end of the second year of a community‐based, placebo‐controlled trial of annual ivermectin chemotherapy in northern Nigeria. No significant differences were seen in the distribution and phenotype of leucocytes in nodules from ivermectin‐ and placebo‐treated individuals. Live adult worms were only seen in nine of the 21 nodules examined. Three regions were clearly discernible within nodules containing both live and dead worms; an outer fibrovascular capsule (zone A), an inner adult worm bundle with surrounding hyaline extracellular matrix interspersed with solitary cells (zone B), and a dense cellular infiltrate surrounding and in contact with a variable proportion of the worm (zone C). Macrophages were the predominant cell type in all zones of the nodule. Those in zone B were distinguished by their dendritic morphology and strong reactivity with MoAbs directed against class II molecules. FcRl (CD64) and CD68, whereas macrophages in zone C were larger, more heterogeneous in shape, and were distinguished by strong reactivity with MoAbs directed against CR4 (CDlIc, CD18) and MRP8/MRP14, and with MoAb 24. T cells were found primarily in zones A and C, whilst eosinophils were found in only six nodules. A unique staining pattern was seen using MoAbs reacting with the calcium‐binding protein MRP8/MRPI4. Most macrophages in zones A and B were negative; however, where the occasional positive macrophage was seen in zone B, MRP8/MRP14 was also found around the cell and on the neighbouring worm surface, giving the impression that MRP8/ MRP14 was being secreted onto the adult worm. Macrophages in zone C were also MRP8/MRP14‐positive, and often the whole infiltrate was surrounded with extracellular MRP8/MRP14, with greatest concentration seen adjacent to the worm. M RP8/MRP14 was not identified on the surface of microfilariae (MF) within the same nodules. Since MRP8/MRP14 was seen on the adult worm in the absence of a leucocytic infiltrate, it may have an early role to play in the immune response to Onchocerca volvulus .