@article {1667,
	title = {How are bacterial cells degraded by leukocytes in vivo? An enigma},
	journal = {Clinical Immunology Newsletter},
	volume = {4},
	number = {11},
	year = {1983},
	pages = {147-153},
	abstract = {This year marks the centennial anniversary
of Elie Metchnikoff{\textquoteright}s discovery
of the pivotal role played by
"professional" phagocytes in body defenses
against invading microorganisms.
His cellular theory dealt with
the phagocytic events and the postphagocytic
killing, and also alluded to
the digestion of the internalized bacteria
by the "cystases," later shown to
be associated with the lysosomal apparatus
of leukocytes. Fo date, despite
the fact that numerous studies have described
in great detail the mechanisms
by which serum and leukocytes kill
microorganisms (1, 8, 13, 24), surprisingly
little is actually known about the
biochemical pathways of degradation
and mechanisms of disposal of microbial
constituents once they have been
sequestered within phagolysosomes (3,
9, 10, 13, 24). It is usually taken for
granted that the numerous hydrolytic
enzymes, including the key bacteriolytic
enzyme lysozyme (muramidase),
present in lysosomes of "professional"
phagocytic cells [granulocytes
or polymorphonuclear neutrophils
(PMNs), and macrophages] are capable,
(at least theoretically) of stripping
off bacterial coats, thus exposing
the peptidoglycan to cleavage by touramidase.
Yet, the majority of pathogenic
microorganisms are highly refractory
to lysozyme action (9, 10,
17). One should also bear in mind
that, while a massive breakdown of
microbial cell walls eventually may
lead to a bactericidal reaction, the
mere killing of a microorganisms, either
by leukocyte or by serum factors,
may not necessarily be followed by a
bacteriolytic reaction. The importance
of elucidating the mechanism of microbial
biodegradation in tissues stems
from the observation that in many infectious
diseases there is "storage" of
nonbiodegraded microbial cell wall
components within macrophages for
long periods, which may be responsible
for the perpetuation and propagation
of chronic inflammatory sequelae
and tissue destruction (10, 18).
We have recently postulated (11,
14, 15) that bacteriolysis, and the biochemical
degradation that ensues
after bacteria have been attacked by
serum or by leukocytes, may involve
close cooperation among heat-stable
serum factors, cationic proteins and
phospholipase A2 of leukocytes, and
heat-labile endogenous bacterial autolyric
wall enzymes. This cooperation
is affected markedly by anionic polyelectrolytes,
likely to accumulate in inflammatory
exudates, which may shut
down autolysis and, thus, contribute to
unfavorable postinfectious sequelae
(10, 19).
The present communication is a
summary of efforts from our laboratory
to gain insight into the mechanisms
of lysis of Staphylococcus attreus,
chosen as a model, by lysosomal
enzymes of human blood leukocytes
(3, 8-11, 14, 15, 19).},
	author = {Isaac Ginsburg and Meir Lahav}
}
