A review of the innate immune defence of the human foetus and newborn, with the emphasis on antimicrobial peptides

Antimicrobial peptides are an important component of the innate immune defence. Mycobacterium avium subsp. hominissuis (M. avium) is an organism that establishes contact with the respiratory and gastrointestinal mucosa as a necessary step for infection. M. avium is resistant to high concentrations of polymyxin B, a surrogate for antimicrobial peptides. To determine gene-encoding proteins that are associated with this resistance, we screened a transposon library of M. avium strain 104 for susceptibility to polymyxin B. Ten susceptible mutants were identified and the inactivated genes sequenced. The great majority of the genes were related to cell wall synthesis and permeability. The mutants were then examined for their ability to enter macrophages and to survive macrophage killing. Three clones among the mutants had impaired uptake by macrophages compared with the WT strain, and all ten clones were attenuated in macrophages. The mutants were also shown to be susceptible to cathelicidin (LL-37), in contrast to the WT bacterium. All but one of the mutants were significantly attenuated in mice. In conclusion, this study indicated that the M. avium envelope is the primary defence against host antimicrobial peptides.

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Innate immune defence mechanisms of tench,Tinca tinca(L.), naturally infected with the tapewormMonobothrium wageneri

Parasite Immunology ◽

10.1111/j.1365-3024.2012.01373.x ◽

2012 ◽

Vol 34 (11) ◽

pp. 511-519 ◽

Cited By ~ 12

Author(s):

B. S. DEZFULI ◽

A. LUI ◽

L. GIARI ◽

G. CASTALDELLI ◽

A. P. SHINN ◽

...

Keyword(s):

Innate Immune ◽

Immune Defence ◽

Tinca Tinca ◽

Defence Mechanisms ◽

Innate Immune Defence ◽

Tench Tinca Tinca

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Nucleated Fish Erythrocyte Extracellular Traps (FEETs) release is an evolutionary conserved immune defence process

10.1101/2021.08.10.455826 ◽

2021 ◽

Author(s):

Giulia Rinaldi ◽

Neila Alvarez de Haro ◽

Andrew Paul Desbois ◽

Calum T. Robb ◽

Adriano G. Rossi

Keyword(s):

Calcium Ionophore ◽

Innate Immune ◽

Oxygen Species ◽

Immune Defence ◽

Mitochondrial Reactive Oxygen Species ◽

Antimicrobial Proteins ◽

Extracellular Traps ◽

Kinase C ◽

Innate Immune Defence ◽

Fish Erythrocyte

Fish erythrocytes remain nucleated for their life-span, unlike mammalian erythrocytes which undergo enucleation. Asides transportation of oxygen, fish erythrocytes are capable of several immune defence processes. Nucleated fish erythrocytes represent prime candidates for carrying out ETotic responses. ETosis is an evolutionary conserved innate immune defence process found in both vertebrates and invertebrates, which involves the extrusion of DNA studded with antimicrobial proteins into the extracellular space serving to trap and kill microorganisms. In this report, we demonstrate that fish erythrocytes isolated from Danio rerio (zebrafish) produce ETotic-like responses when exposed to chemical and physiological stimuli. Salmo salar (Atlantic salmon) erythrocytes produce similar ETotic responses. We have termed these ET-like formations Fish Erythrocyte Extracellular Traps (FEETs). Interestingly, we discovered that mammalian inducers of NETosis, such as the protein kinase C (PKC) activator phorbol 12‐myristate 13‐acetate and the calcium ionophore ionomycin induced FEETs. Moreover, we found that FEETs are dependent upon activation of PKC and generation of mitochondrial reactive oxygen species. Thus, this brief report represents the first demonstration that fish erythrocytes can exhibit ETotic-like responses, unveiling a previously unknown function of nucleated erythrocytes, and sheds new light on the innate immune arsenal of erythrocytes.

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