Host cell specific activity of RTX toxins from haemolytic Actinobacillus equuli and Actinobacillus suis

Kuhnert, Peter; Berthoud, H.; Straub, Reto; Frey, Joachim (2003). Host cell specific activity of RTX toxins from haemolytic Actinobacillus equuli and Actinobacillus suis. Veterinary microbiology, 92(1-2), pp. 161-167. Amsterdam: Elsevier 10.1016/S0378-1135(02)00353-X

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We assessed and compared host cell specificity of the haemolytic and cytotoxic activity of the RTX toxins from Actinobacillus equuli, an equine pathogen, and Actinobacillus suis, which is pathogenic for pigs. The two bacterial species are closely related, phenotypically as well as phylogenetically, sharing the same 16S rRNA gene sequence. Both species contain specific protein toxins from the family of pore-forming RTX toxins, however, the two species differ in their RTX toxin profiles. Haemolytic A. equuli contains the operon for the Aqx toxin, whereas A. suis harbours genes for ApxI and ApxII. We tested the toxic activity of the corresponding proteins on erythrocytes as well as on lymphocytes isolated from horse and pig blood. The strength of the haemolytic activity for each of the toxins was independent of the origin of erythrocytes. When testing cytotoxic activity, the Aqx protein showed a higher toxic effect for horse lymphocytes than for porcine lymphocytes. On the other hand, ApxI and ApxII showed a strong cytotoxic effect on porcine lymphocytes and a reduced toxicity for horse lymphocytes; the toxicity of ApxII was generally much lower than ApxI. Our results indicate a host species specificity of the toxic activity of RTX toxins Aqx of A. equuli and ApxI and ApxII of A. suis.

Item Type:

Journal Article (Original Article)


05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP) > Institute of Veterinary Bacteriology
05 Veterinary Medicine > Department of Clinical Veterinary Medicine (DKV) > Equine Clinic

UniBE Contributor:

Kuhnert, Peter; Straub, Reto and Frey, Joachim


600 Technology > 630 Agriculture
500 Science
500 Science > 570 Life sciences; biology








Peter Kuhnert-Ryser

Date Deposited:

24 Jan 2014 08:50

Last Modified:

25 Dec 2014 06:06

Publisher DOI:


PubMed ID:


Uncontrolled Keywords:

RTX toxins, Host specificity, Pig pathogen, Horse pathogen, Cytotoxicity, Haemolysis




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