title: C57Bl/6 and BALB/c mice have similar neutrophil response to acute Streptococcus pneumoniae sinus infections.
abstract: BACKGROUND
  Previous investigations have shown that mice with a tendency toward a T(H)1 or T(H)2 lymphocyte response manifest different reactions to inoculation with the parasite Leishmania major. BALB/c mice (with a tendency for a T(H)2 response) showed evidence of systemic infection, whereas C57Bl/6 mice (with a tendency for a T(H)1 response) showed only a local reaction.
  
  
  OBJECTIVE
  To investigate whether BALB/c and C57Bl/6 mice respond differently to acute bacterial infection of the sinuses.
  
  
  METHODS
  We inoculated the nasal cavities of C57Bl/6 and BALB/c mice with Streptococcus pneumoniae (type ATCC59), or with broth as a control. The mice were humanely killed 2, 5, 10, and 14 days after inoculation. Their heads were fixed, decalcified, and embedded in paraffin blocks. Sections were stained with hematoxylin and eosin, and the degree of inflammation was quantified by the number of neutrophils per square millimeter of the sinus mucosa and the percentage of the sinus cavity occupied by neutrophil clusters.
  
  
  RESULTS
  Both groups of mice showed evidence of inflammation that was significantly greater than controls (P =.01), with no difference between groups. There was a correlation between the number of neutrophils per square millimeter in the sinus mucosa and the percentage of neutrophil clusters (C57Bl/6 mice, r = 0.37, P<.001; BALB/c mice, r = 0.20, P<.001). In the infected mice, the number of infiltrating neutrophils was significantly greater (P<.001) in anatomically lower (dependent) areas of the sinuses compared with the upper areas.
  
  
  CONCLUSIONS
  Unlike leishmaniasis, acute bacterial sinusitis is not affected by the tendency of the host to favor either a T(H)1 or T(H)2 response.
authors.affiliation: Section of Otolaryngology-Head and Neck Surgery, The University of Chicago, Chicago, IL 60637, USA.
authors.forename: U
authors.initials: U
authors.lastname: Gabr
authors.forename: Y S
authors.initials: YS
authors.lastname: Won
authors.forename: S
authors.initials: S
authors.lastname: Boonlayangoor
authors.forename: K
authors.initials: K
authors.lastname: Thompson
authors.forename: F M
authors.initials: FM
authors.lastname: Baroody
authors.forename: R M
authors.initials: RM
authors.lastname: Naclerio
mesh_terms: D000208:Acute Disease; D000818:Animals; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000276:immunology* / Q000473:pathology; D011008:Pneumococcal Infections / Q000276:immunology* / Q000473:pathology; D020545:Respiratory Mucosa / Q000473:pathology; D012852:Sinusitis / Q000276:immunology* / Q000473:pathology; D013296:Streptococcus pneumoniae; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology