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Quantitative discrimination of hepatic reticuloendothelial clearance and phagocytic killing
Author(s) -
Klein Andrew,
Zhadkewich Michael,
Margolick Joseph,
Winkelstein Jerry,
Bulkley Gregory
Publication year - 1994
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.55.2.248
Subject(s) - mononuclear phagocyte system , biology , zymosan , clearance , opsonin , in vivo , hepatic function , phagocytosis , pharmacology , immunology , endocrinology , in vitro , biochemistry , medicine , microbiology and biotechnology , urology
An in vivo assay to quantify simultaneously two important components of hepatic reticuloendothelial system (RES) function—clearance and phagocytic killing—was developed in the rat. Intravenously injected E. coli labeled with Na 51 Cr and 5‐[ 123 I]‐iodo‐2′‐deoxyuridine were cleared rapidly from the blood primarily by the liver. While hepatic 51 Cr levels remained stable for 24 h following inoculation and provided a reliable measurement of clearance, hepatic 125 I decreased over time. Hepatic 125 I, calculated by sampling whole liver homogenates, accurately reflects the number of viable bacteria recovered from quantitative cultures of the same homogenates, thus validating this assay as a measure of bacteria killing. Pre‐treatment of rats with substances previously shown to affect RES function (gadolinium, zymosan, and sheep erythrocytes) were found to selectively modulate clearance and/or killing. The correlation between hepatic isotope levels and viable hepatic bacteria, the gold standard for assessing the capacity of the liver to remove organisms from the blood and kill them, was preserved under conditions of up‐ and down‐regulation of RES function. The ability to quantitatively discriminate two distinct components of the hepatic RES should provide a useful tool for future investigations of altered RES function. J. Leukoc. Biol. 55: 248–252; 1994.