Session Type: ePosters
Session Title: ePosters
Authors(s): P. Bhola (1, 2), A.W. Sturm (1)
Authors Affiliations(s): (1) University of KwaZulu-Natal, South Africa, (2) National Health Laboratory Services, South Africa
Background:
Cryptococcal meningitis is an important opportunistic infection in immunocompromised patients. It is well established that this form of meningitis is characterized by a relative paucity of neutrophils in the cerebrospinal fluid (CSF) compared to bacterial meningitis. There has been speculation and research undertaken previously to understand this phenomenon, however, little information is available in human studies. Furthermore, there is insufficient information on Toll-like receptor (TLR) expression and function in the human central nervous system (CNS). This study investigated the effect of the capsular material of Cryptococcus neoformans on neutrophil recruitment at the site of infection and determined whether downregulation occurs at the level of TLR gene expression.
Methods:Clinical information was collected from patients with cryptococcal meningitis and baseline blood and CSF investigations were performed, which included neutrophil quantification in CSF and blood specimens. The cryptococcus capsule size was measured using Anthony’s capsule staining technique in each isolate. Shed capsular material was quantified in individual CSF specimens using the cryptococcal latex agglutination test. The extent of neutrophil chemotaxis inhibition by individual strains of C. neoformans was determined by using a Transwell migration assay. Toll-like receptor (TLR)2 and TLR4 gene expression induced by individual C. neoformans isolates in human microglial cells were quantified. The possible associations among these experiments were subsequently evaluated.
Results:A paucity of neutrophils in the CSF was observed. Significantly, patients presenting with fever had higher CSF neutrophil counts (p=0.003), a relationship which, in cryptococcal meningitis has not been explored previously. Patients with lower CSF neutrophil counts shed more capsular material in the CSF (p=0.03). Chemotaxis inhibition occurred in almost 70% of tested isolates. The concentration of shed capsular material in this group was higher compared to the group with no chemotaxis inhibition. Majority of isolates expressed downregulation for TLR2 and TLR4 in microglial cells exposed to C. neoformans. CSF neutrophil counts were lower in this group.
Conclusions:These findings imply that the capsular components of C. neoformans downregulated recruitment of neutrophils into the CSF. Downregulation occurred at the level of TLR expression. This study is among the first to examine host-pathogen relationship in human microglial cells.
Keyword(s): neutrophil chemotaxis, toll-like receptor, microglial cellsCOI Institutional Grants: Yes
Session Type: ePosters
Session Title: ePosters
Authors(s): P. Bhola (1, 2), A.W. Sturm (1)
Authors Affiliations(s): (1) University of KwaZulu-Natal, South Africa, (2) National Health Laboratory Services, South Africa
Background:
Cryptococcal meningitis is an important opportunistic infection in immunocompromised patients. It is well established that this form of meningitis is characterized by a relative paucity of neutrophils in the cerebrospinal fluid (CSF) compared to bacterial meningitis. There has been speculation and research undertaken previously to understand this phenomenon, however, little information is available in human studies. Furthermore, there is insufficient information on Toll-like receptor (TLR) expression and function in the human central nervous system (CNS). This study investigated the effect of the capsular material of Cryptococcus neoformans on neutrophil recruitment at the site of infection and determined whether downregulation occurs at the level of TLR gene expression.
Methods:Clinical information was collected from patients with cryptococcal meningitis and baseline blood and CSF investigations were performed, which included neutrophil quantification in CSF and blood specimens. The cryptococcus capsule size was measured using Anthony’s capsule staining technique in each isolate. Shed capsular material was quantified in individual CSF specimens using the cryptococcal latex agglutination test. The extent of neutrophil chemotaxis inhibition by individual strains of C. neoformans was determined by using a Transwell migration assay. Toll-like receptor (TLR)2 and TLR4 gene expression induced by individual C. neoformans isolates in human microglial cells were quantified. The possible associations among these experiments were subsequently evaluated.
Results:A paucity of neutrophils in the CSF was observed. Significantly, patients presenting with fever had higher CSF neutrophil counts (p=0.003), a relationship which, in cryptococcal meningitis has not been explored previously. Patients with lower CSF neutrophil counts shed more capsular material in the CSF (p=0.03). Chemotaxis inhibition occurred in almost 70% of tested isolates. The concentration of shed capsular material in this group was higher compared to the group with no chemotaxis inhibition. Majority of isolates expressed downregulation for TLR2 and TLR4 in microglial cells exposed to C. neoformans. CSF neutrophil counts were lower in this group.
Conclusions:These findings imply that the capsular components of C. neoformans downregulated recruitment of neutrophils into the CSF. Downregulation occurred at the level of TLR expression. This study is among the first to examine host-pathogen relationship in human microglial cells.
Keyword(s): neutrophil chemotaxis, toll-like receptor, microglial cellsCOI Institutional Grants: Yes
University of KwaZulu-Natal and National Health Laboratory Service
Session Type: ePosters
Session Title: ePosters
Authors(s): P. Bhola (1, 2), A.W. Sturm (1)
Authors Affiliations(s): (1) University of KwaZulu-Natal, South Africa, (2) National Health Laboratory Services, South Africa
Background:
Cryptococcal meningitis is an important opportunistic infection in immunocompromised patients. It is well established that this form of meningitis is characterized by a relative paucity of neutrophils in the cerebrospinal fluid (CSF) compared to bacterial meningitis. There has been speculation and research undertaken previously to understand this phenomenon, however, little information is available in human studies. Furthermore, there is insufficient information on Toll-like receptor (TLR) expression and function in the human central nervous system (CNS). This study investigated the effect of the capsular material of Cryptococcus neoformans on neutrophil recruitment at the site of infection and determined whether downregulation occurs at the level of TLR gene expression.
Methods:Clinical information was collected from patients with cryptococcal meningitis and baseline blood and CSF investigations were performed, which included neutrophil quantification in CSF and blood specimens. The cryptococcus capsule size was measured using Anthony’s capsule staining technique in each isolate. Shed capsular material was quantified in individual CSF specimens using the cryptococcal latex agglutination test. The extent of neutrophil chemotaxis inhibition by individual strains of C. neoformans was determined by using a Transwell migration assay. Toll-like receptor (TLR)2 and TLR4 gene expression induced by individual C. neoformans isolates in human microglial cells were quantified. The possible associations among these experiments were subsequently evaluated.
Results:A paucity of neutrophils in the CSF was observed. Significantly, patients presenting with fever had higher CSF neutrophil counts (p=0.003), a relationship which, in cryptococcal meningitis has not been explored previously. Patients with lower CSF neutrophil counts shed more capsular material in the CSF (p=0.03). Chemotaxis inhibition occurred in almost 70% of tested isolates. The concentration of shed capsular material in this group was higher compared to the group with no chemotaxis inhibition. Majority of isolates expressed downregulation for TLR2 and TLR4 in microglial cells exposed to C. neoformans. CSF neutrophil counts were lower in this group.
Conclusions:These findings imply that the capsular components of C. neoformans downregulated recruitment of neutrophils into the CSF. Downregulation occurred at the level of TLR expression. This study is among the first to examine host-pathogen relationship in human microglial cells.
Keyword(s): neutrophil chemotaxis, toll-like receptor, microglial cellsCOI Institutional Grants: Yes
Session Type: ePosters
Session Title: ePosters
Authors(s): P. Bhola (1, 2), A.W. Sturm (1)
Authors Affiliations(s): (1) University of KwaZulu-Natal, South Africa, (2) National Health Laboratory Services, South Africa
Background:
Cryptococcal meningitis is an important opportunistic infection in immunocompromised patients. It is well established that this form of meningitis is characterized by a relative paucity of neutrophils in the cerebrospinal fluid (CSF) compared to bacterial meningitis. There has been speculation and research undertaken previously to understand this phenomenon, however, little information is available in human studies. Furthermore, there is insufficient information on Toll-like receptor (TLR) expression and function in the human central nervous system (CNS). This study investigated the effect of the capsular material of Cryptococcus neoformans on neutrophil recruitment at the site of infection and determined whether downregulation occurs at the level of TLR gene expression.
Methods:Clinical information was collected from patients with cryptococcal meningitis and baseline blood and CSF investigations were performed, which included neutrophil quantification in CSF and blood specimens. The cryptococcus capsule size was measured using Anthony’s capsule staining technique in each isolate. Shed capsular material was quantified in individual CSF specimens using the cryptococcal latex agglutination test. The extent of neutrophil chemotaxis inhibition by individual strains of C. neoformans was determined by using a Transwell migration assay. Toll-like receptor (TLR)2 and TLR4 gene expression induced by individual C. neoformans isolates in human microglial cells were quantified. The possible associations among these experiments were subsequently evaluated.
Results:A paucity of neutrophils in the CSF was observed. Significantly, patients presenting with fever had higher CSF neutrophil counts (p=0.003), a relationship which, in cryptococcal meningitis has not been explored previously. Patients with lower CSF neutrophil counts shed more capsular material in the CSF (p=0.03). Chemotaxis inhibition occurred in almost 70% of tested isolates. The concentration of shed capsular material in this group was higher compared to the group with no chemotaxis inhibition. Majority of isolates expressed downregulation for TLR2 and TLR4 in microglial cells exposed to C. neoformans. CSF neutrophil counts were lower in this group.
Conclusions:These findings imply that the capsular components of C. neoformans downregulated recruitment of neutrophils into the CSF. Downregulation occurred at the level of TLR expression. This study is among the first to examine host-pathogen relationship in human microglial cells.
Keyword(s): neutrophil chemotaxis, toll-like receptor, microglial cellsCOI Institutional Grants: Yes