TABLE 2.

Percent disrupted oocysts and percent binding of anti-TDmAb to the nuclei of irradiated sporozoites in C. parvum and C. hominis oocysts^a

No. of freeze-thaw cycles	% Disrupted oocystb,c		% Antibody bindingb,d
	C. parvum	C. hominis	C. parvum	C. hominis
5	97.3 ± 0.2	96.5 ± 1.0	99.3 ± 0.7	99.6 ± 0.4
7	97.2 ± 1.0	95.3 ± 0.7	100 ± 0.0	99.0 ± 1.0
10	98.1 ± 1.3	97.6 ± 2.1	99.0 ± 1.0	99.6 ± 0.4

^aC. parvum and C. hominis oocysts were air dried on microscope slides and exposed to different numbers of cycles of freezing and thawing. The disruption of oocysts and their contents was visualized by labeling with FITC-CmAb and DAPI. The binding of anti-TDmAb to the nuclei of irradiated sporozoites within oocysts was visualized by labeling with anti-TDmAb, DAPI, and FITC-CmAb. Samples were examined by epifluorescence and Nomarski DIC microscopy.

^bResults are given as means ± SDs. The mean percentage was obtained by enumerating 300 oocysts per treatment (n = 3). Results are not statistically significantly different at P < 0.05.

^cDisrupted oocysts had a morphological break in the perimeter of the oocyst wall (Fig. 2, images in columns 2 and 3; Fig. 3, images in columns 3 and 4).

^dPercent antibody binding indicates the number of oocysts containing sporozoites with anti-TDmAb⁺, DAPI⁺ nuclei (n = 300 observations per sporozoite treatment).