Toxin/

Enzyme

Location of gene

Molecular mass (kDa)

LD₅₀

(mice)

Main targets

Biological activity of toxin

References

Alpha toxin (CPA)

Chromosome

43

3 µg

Phosphatidylcholine, Sphingomyelin

· Essential for growth & dissemination of infection

· Hemolysis via phospholipase & sphingomyelinase activity

· Inhibition of neutrophil & erythroid differentiation

· Vasoconstriction via activation of arachidonic acid cascade

[58] - [63]

Beta toxin (CPB)

Plasmid

35

<400 ng

Intestinal epithelial,

Endothelial cells, sensory neurons

· Necrosis of intestinal mucosal epithelium and vascular endothelium

· Oedema, dermonecrosis & plasma extravasation though release of substance P from toxin-stimulated sensory neurons

· Cytotoxic to platelets

[64] [65] [66] [67]

Epsilon toxin (ETX)

Plasmid

33

70 - 100 ng

Endothelial cells, mucosal tight junctions, lymphocytes, all vital organs including brain

· Increased permeability of intestine & blood vessels

· Degeneration of distal tubule cells in kidney

· Cerebral oedema & necrosis via damage to BBB

· Demyelination by causing necrosis of oligodendrocytes

· Release of glutamate by stimulating target cells in cerebellum & hippocampus

· Cytotoxic to lymphocytes

[5] [54] [68] - [74]

Iota toxin (ITX)

Plasmid

Ia-48

Ib-72

40 µg

Cell cytoskeleton (actin)

· Increased permeability & necrosis of intestinal epithelial cells by actin depolymerization

[75] [76] [77]

Enterotoxin (CPE)

Chromosome or plasmid

35

81 µg

Claudins of tight junctions

· Loss of contact between intestinal epithelial cells

[78] [79] [80] [81]

Necrotic enteritis B-like toxin (NetB)

Plasmid

33

-

Enterocytes

· Destruction of extracellular matrix, lamina propria and intercellular junctions

[82]

Beta-2 toxin (CPB2)

Plasmid

28

160 µg

Enterocytes, endothelial cells

· Dermonecrosis, oedema & enterotoxic

[83]

Perfringolysin O (PFO)/Theta toxin

Chromosome

54

15 µg

Enterocytes, endothelial cells, leucocytes

· Act synergistically with CPA & ETX

· Disruption of endothelial integrity

· Leukocytotoxic at high dose

[84] [85] [86]

Toxin C. perfringens large cytotoxin

(TpeL)

Plasmid

191

600 µg

GTPase Ras

· Inactivation of Ras protein with resultant disruption of intercellular junctions & increased cell barrier permeability

[87] [88]

Lamba toxin

Plasmid

36

-

Endothelial cells

· Increases vascular permeability

· Activates prototoxin forms of ETX & ITX

[89] [90]

Delta toxin

Plasmid

32

-

Different blood cells, GM2 ganglioside on cell membranes

· Cytotoxic to various eukaryotic cells such as macrophages, platelets, erythrocytes including various cell lines

[91]

Necrotizing enteritis toxin F (NetF)

Plasmid

34.3

-

Sialic acid on cell membranes

· Cytotoxic to various cell lines such as equine ovarian, porcine kidney 15, Vero cell line etc.

[92] [93]

Sialidase (NanH, NanI, NanJ)

Chromosome

43, 77, 129

-

Sialic acid linkages

· Alters host cell surface to promote bacterial attachment & colonization

· Increased ETX binding & cytotoxicity

[52] [53] [94]