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Updated: Oct 5, 2026
Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae
Published on: January 17, 2014
C57Bl/6 and BALB/c mice have similar neutrophil response to acute Streptococcus pneumoniae sinus infections
U Gabr1, Y S Won, S Boonlayangoor
1Section of Otolaryngology-Head and Neck Surgery, The University of Chicago, Chicago, IL 60637, USA.
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.
Conclusion:
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.
Insights
Host immune response type does not affect acute bacterial sinusitis outcomes in mice. Both T(H)1 and T(H)2 leaning mice showed similar inflammation levels after Streptococcus pneumoniae infection.
Area of Science:
- Immunology
- Microbiology
- Otolaryngology
Background:
- Different mouse strains (BALB/c and C57Bl/6) exhibit distinct T(H)1/T(H)2 lymphocyte responses.
- Previous studies showed varied responses to Leishmania major infection based on T(H)1/T(H)2 bias.
Purpose of the Study:
- To determine if BALB/c and C57Bl/6 mice exhibit differential responses to acute bacterial sinusitis.
- Investigate the role of T(H)1 vs. T(H)2 immune responses in bacterial sinus infections.
Main Methods:
- Mice (BALB/c and C57Bl/6) were intranasally inoculated with Streptococcus pneumoniae or control broth.
- Nasal tissues were collected at multiple time points (2, 5, 10, 14 days) post-inoculation.
- Histological analysis quantified neutrophil infiltration and inflammation in sinus mucosa.
Main Results:
- Both mouse strains showed significant inflammation compared to controls (P=.01).
- No significant difference in inflammation was observed between BALB/c and C57Bl/6 mice.
- Neutrophil infiltration was greater in dependent sinus areas compared to upper areas (P<.001).
Conclusions:
- Acute bacterial sinusitis severity is independent of a T(H)1 or T(H)2 immune response bias in mice.
- Findings contrast with observations in parasitic infections like leishmaniasis.
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