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Differential phagocytosis of white versus opaque Candida albicans by Drosophila and mouse phagocytes.

Lohse MB, Johnson AD - PLoS ONE (2008)

Bottom Line: The human fungal pathogen Candida albicans resides asymptomatically in the gut of most healthy people but causes serious invasive diseases in immunocompromised patients.This difference is seen both in the overall percentage of cultured cells that phagocytose white versus opaque C. albicans and in the average number of C. albicans taken up by each phagocytic cell.We conclude that susceptibility to phagocytosis by cells of the innate immune system is an important distinction between white and opaque C. albicans, and propose that one role of switching from the prevalent white form into the rarer opaque form may be to allow C. albicans to escape phagocytosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California, USA.

ABSTRACT
The human fungal pathogen Candida albicans resides asymptomatically in the gut of most healthy people but causes serious invasive diseases in immunocompromised patients. Many C. albicans strains have the ability to stochastically switch between distinct white and opaque cell types, but it is not known with certainty what role this switching plays in the physiology of the organism. Here, we report a previously undescribed difference between white and opaque cells, namely their interaction with host phagocytic cells. We show that both Drosophila hemocyte-derived S2 cells and mouse macrophage-derived RAW264.7 cells preferentially phagocytose white cells over opaque cells. This difference is seen both in the overall percentage of cultured cells that phagocytose white versus opaque C. albicans and in the average number of C. albicans taken up by each phagocytic cell. We conclude that susceptibility to phagocytosis by cells of the innate immune system is an important distinction between white and opaque C. albicans, and propose that one role of switching from the prevalent white form into the rarer opaque form may be to allow C. albicans to escape phagocytosis.

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M. musculus RAW cells more efficiently phagocytose white than opaque C. albicans.(A) M. musculus RAW cells were co-incubated with white or opaque C. albicans for 1 hour then stained using the same methods as for S2 cells. The number of RAW cells phagocytosing one or more C. albicans cells was determined. (B) The number of C. albicans cells phagocytosed was quantified and used to calculate and plot the total number of C. albicans cells phagocytosed divided by the number of RAW cells scored, referred to as the phagocytic index. (C) M. musculus RAW cells were co-incubated with equal numbers of white and opaque C. albicans for 1 hour. The number of RAW cells phagocytosing one or more C. albicans cells was determined. (D) For the same RAW cells, the number of C. albicans cells phagocytosed was quantified and the phagocytic index plotted. 100 RAW cells were counted for each data set and values plotted are the average of four (A,B) or six (C,D) data sets with error bars representing standard deviation. Statistical significance of differences from the a/a whites was determined using a t-test and differences with p<.001 are marked with an asterisk.
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pone-0001473-g004: M. musculus RAW cells more efficiently phagocytose white than opaque C. albicans.(A) M. musculus RAW cells were co-incubated with white or opaque C. albicans for 1 hour then stained using the same methods as for S2 cells. The number of RAW cells phagocytosing one or more C. albicans cells was determined. (B) The number of C. albicans cells phagocytosed was quantified and used to calculate and plot the total number of C. albicans cells phagocytosed divided by the number of RAW cells scored, referred to as the phagocytic index. (C) M. musculus RAW cells were co-incubated with equal numbers of white and opaque C. albicans for 1 hour. The number of RAW cells phagocytosing one or more C. albicans cells was determined. (D) For the same RAW cells, the number of C. albicans cells phagocytosed was quantified and the phagocytic index plotted. 100 RAW cells were counted for each data set and values plotted are the average of four (A,B) or six (C,D) data sets with error bars representing standard deviation. Statistical significance of differences from the a/a whites was determined using a t-test and differences with p<.001 are marked with an asterisk.

Mentions: After a 1 hour co-incubation, the percentage of RAW cells that had phagocytosed at least one white C. albicans was roughly 5 to 10-fold greater than for opaques (FIG. 4A). As with S2 cells, a/α and a/a whites were phagocytosed at similar rates (FIG. 4A) as were equivalent α/α strains (data not shown). We also monitored the total number of C. albicans phagocytosed and used this to calculate the number of C. albicans cells phagocytosed per RAW cell scored. The value for white cells was approximately 10-fold greater than opaques after one hour (FIG. 4B).


Differential phagocytosis of white versus opaque Candida albicans by Drosophila and mouse phagocytes.

Lohse MB, Johnson AD - PLoS ONE (2008)

M. musculus RAW cells more efficiently phagocytose white than opaque C. albicans.(A) M. musculus RAW cells were co-incubated with white or opaque C. albicans for 1 hour then stained using the same methods as for S2 cells. The number of RAW cells phagocytosing one or more C. albicans cells was determined. (B) The number of C. albicans cells phagocytosed was quantified and used to calculate and plot the total number of C. albicans cells phagocytosed divided by the number of RAW cells scored, referred to as the phagocytic index. (C) M. musculus RAW cells were co-incubated with equal numbers of white and opaque C. albicans for 1 hour. The number of RAW cells phagocytosing one or more C. albicans cells was determined. (D) For the same RAW cells, the number of C. albicans cells phagocytosed was quantified and the phagocytic index plotted. 100 RAW cells were counted for each data set and values plotted are the average of four (A,B) or six (C,D) data sets with error bars representing standard deviation. Statistical significance of differences from the a/a whites was determined using a t-test and differences with p<.001 are marked with an asterisk.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2198939&req=5

pone-0001473-g004: M. musculus RAW cells more efficiently phagocytose white than opaque C. albicans.(A) M. musculus RAW cells were co-incubated with white or opaque C. albicans for 1 hour then stained using the same methods as for S2 cells. The number of RAW cells phagocytosing one or more C. albicans cells was determined. (B) The number of C. albicans cells phagocytosed was quantified and used to calculate and plot the total number of C. albicans cells phagocytosed divided by the number of RAW cells scored, referred to as the phagocytic index. (C) M. musculus RAW cells were co-incubated with equal numbers of white and opaque C. albicans for 1 hour. The number of RAW cells phagocytosing one or more C. albicans cells was determined. (D) For the same RAW cells, the number of C. albicans cells phagocytosed was quantified and the phagocytic index plotted. 100 RAW cells were counted for each data set and values plotted are the average of four (A,B) or six (C,D) data sets with error bars representing standard deviation. Statistical significance of differences from the a/a whites was determined using a t-test and differences with p<.001 are marked with an asterisk.
Mentions: After a 1 hour co-incubation, the percentage of RAW cells that had phagocytosed at least one white C. albicans was roughly 5 to 10-fold greater than for opaques (FIG. 4A). As with S2 cells, a/α and a/a whites were phagocytosed at similar rates (FIG. 4A) as were equivalent α/α strains (data not shown). We also monitored the total number of C. albicans phagocytosed and used this to calculate the number of C. albicans cells phagocytosed per RAW cell scored. The value for white cells was approximately 10-fold greater than opaques after one hour (FIG. 4B).

Bottom Line: The human fungal pathogen Candida albicans resides asymptomatically in the gut of most healthy people but causes serious invasive diseases in immunocompromised patients.This difference is seen both in the overall percentage of cultured cells that phagocytose white versus opaque C. albicans and in the average number of C. albicans taken up by each phagocytic cell.We conclude that susceptibility to phagocytosis by cells of the innate immune system is an important distinction between white and opaque C. albicans, and propose that one role of switching from the prevalent white form into the rarer opaque form may be to allow C. albicans to escape phagocytosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California, USA.

ABSTRACT
The human fungal pathogen Candida albicans resides asymptomatically in the gut of most healthy people but causes serious invasive diseases in immunocompromised patients. Many C. albicans strains have the ability to stochastically switch between distinct white and opaque cell types, but it is not known with certainty what role this switching plays in the physiology of the organism. Here, we report a previously undescribed difference between white and opaque cells, namely their interaction with host phagocytic cells. We show that both Drosophila hemocyte-derived S2 cells and mouse macrophage-derived RAW264.7 cells preferentially phagocytose white cells over opaque cells. This difference is seen both in the overall percentage of cultured cells that phagocytose white versus opaque C. albicans and in the average number of C. albicans taken up by each phagocytic cell. We conclude that susceptibility to phagocytosis by cells of the innate immune system is an important distinction between white and opaque C. albicans, and propose that one role of switching from the prevalent white form into the rarer opaque form may be to allow C. albicans to escape phagocytosis.

Show MeSH