The effects of Bruton tyrosine kinase inhibition on chemotaxis and superoxide generation in human neutrophils.
OBJECTIVE
The role of the Bruton tyrosine kinase (Btk) protein in neutrophil function has been evaluated using neutrophils from healthy volunteers after incubation with a Btk inhibitor, leflunomide metabolite analog (LFM-A13), suggesting an important role for Btk in neutrophil function. We sought to determine the role of Btk protein on neutrophil superoxide generation and chemotaxis stimulated by N-formyl-methionine-leucine-phenylalanine (fMLP).


METHODS
Chemotaxis was assayed on agarose gel and superoxide generation by cytochrome C reduction. The affects of LFM-A13 on chemotaxis and superoxide generation in unstimulated and fMLP stimulated neutrophils were studied in Btk deficient neutrophils from XLA patients compared with matched controls analyzed simultaneously.


RESULTS
Chemotaxis and stimulated superoxide production were similar in the normal and Btk deficient neutrophils and were similarly inhibited by LFM-A13. In one patient, LFMA13 had no effect on superoxide generation in Btk deficient neutrophils up to a concentration of 25 microM, while inhibited superoxide production by control neutrophils.


CONCLUSIONS
Our results suggest that Btk does not have a specific role in neutrophil fMLP-stimulated superoxide generation and chemotaxis since these activities were similarly inhibited by LFM-A13 in Btk deficient and normal neutrophils. The lack of superoxide generation following Btk inhibition by LFM-A13 in Btk deficient neutrophils from one patient may suggest some heterogeneity in the role of Btk in fMLP induced neutrophil superoxide generation.
Pediatric Immunology Clinic, Soroka University Medical Center, POB 151, Beer-Sheva, Israel, 84101, broides@bgu.ac.il.
Arnon
A
Broides
Nurit
N
Hadad
Jacov
J
Levy
Rachel
R
Levy
D000293:Adolescent; D000077329:Agammaglobulinaemia Tyrosine Kinase; D000361:Agammaglobulinemia / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D000577:Amides / Q000494:pharmacology*; D016022:Case-Control Studies; D002630:Chemotactic Factors / Q000494:pharmacology; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D015870:Gene Expression; D040181:Genetic Diseases, X-Linked / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D006801:Humans; D007223:Infant; D008297:Male; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D009570:Nitriles / Q000494:pharmacology*; D061251:Primary Cell Culture; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D055815:Young Adult
D000577:Amides; D002630:Chemotactic Factors; C118451:LFM A13; D009570:Nitriles; D047428:Protein Kinase Inhibitors; D013481:Superoxides; D009240:N-Formylmethionine Leucyl-Phenylalanine; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625949:BTK protein, human