ADP-Ribosyltransferase Activity of Pertussis Toxin and Immunomodulation by Bordetella pertussis

Abstract

Pertussis toxin is produced by the causative agent of whooping cough, Bordetella pertussis, and is an adenosine diphosphate (ADP)-ribosyltransferase capable of covalently modifying and thereby inactivating many eukaryotic G proteins involved in cellular metabolism. The toxin is a principal determinant of virulence in whooping cough and is a primary candidate for an acellular pertussis vaccine, yet it is unclear whether the ADP-ribosyltransferase activity is required for both pathogenic and immunoprotective activities. A B. pertussis strain that produced an assembled pertussis holotoxin with only 1 percent of the ADP-ribosyltransferase activity of the native toxin was constructed and was found to be deficient in pathogenic activities associated with B. pertussis including induction of leukocytosis, potentiation of anaphylaxis, and stimulation of histamine sensitivity. Moreover, this mutant strain failed to function as an adjuvant and was less effective in protecting mice from intracerebral challenge infection. These data suggest that the ADP-ribosyltransferase activity is necessary for both pathogenicity and optimum immunoprotection. These findings bear directly on the design of a nontoxic pertussis vaccine.

Identification of an active‐site residue in subunit S1 of pertussis toxin by photocrosslinking to NAD

“…et al, in preparation). A recently reported PT mutant in which four extra amino acids were inserted between Tyr-107 and Val-108 exhibited a 100-fold drop in ADP-ribosyltransferase activity [4], possibly as a result of a conformational change affecting the nicotinamide site around Glu-129.…”

“…Recent achievements in sequencing the PT gene [2,3] have stimulated interest in detoxifying the toxin by genetic engineering [4]. PT is a multimeric protein comprising a B oligomer (subunits $2-$5) that binds to receptors on target ceils, and a catalytic A subunit (S1), an ADP-ribosyltransferase that inactivates host regulatory Gproteins [5].…”

G Proteins Gαi1/3Are Critical Targets for Bordetella pertussis Toxin-Induced Vasoactive Amine Sensitization

“…G␣ i1/3 are critical PTX targets for elicitation of VAASH. The ADP-ribosylating activity of PTX is a well-established mechanism of action whereby PTX inhibits the function of G␣ i/o proteins (52) and is required to elicit the myriad physiological responses following in vivo intoxication, including VAAS and the immune potentiating effects in EAE (18). Conjugation of ADP-ribose to a key cysteine residue in the C terminus of G␣ i/o (but not G␣ s , G␣ q , or G␣ 11 ) proteins prevents the association of the G␣ i/o G␤␥ complex with the GPCR (5,26).…”

“…It is known that PTX-induced VAAS to HA (VAASH) requires intoxication with active holotoxin (18) in a mechanism that presumably involves ADP-ribosylation of the G␣ i/o class of G pro-teins (19). However, there are several G␣ i/o proteins and splice variants but the specific in vivo target(s) associated with PTXinduced VAAS has remained unclear for nearly 30 years.…”

Reversal of the CD4+/CD8+T-Cell Ratio in Lymph Node Cells upon In Vitro Mitogenic Stimulation by Highly Purified, Water-Soluble S3-S4 Dimer of Pertussis Toxin

“…The effects of the toxin on cells of the immune system are multiple and include induction of lymphocytosis, inhibition of macrophage migration, adjuvant activity, and T-cell mitogenicity (18). A number of the biological activities of PT, such as lymphocytosis and adjuvant activity, implicate the enzymatic activity of PT in its toxicity and can be abrogated by inactivation of the S1 subunit (1,5,13). In contrast, PT-associated T-cell mitogenicity is mediated by the B oligomer (9,31,36) and appears to be independent of the enzymatic activity of the toxin, as inactivation of the S1 subunit by mutation has no effect on the mitogenic activity of PT (13,36), while alterations in the B oligomer can totally abrogate the mitogenic activity of PT (15,16,(20)(21)(22).…”