TABLE 3.

Cumultative data on IgA1 protease-producing bacteria and homologous IgA1 protease-inhibiting activity in samples (obtained by method 3) of nasal wash from six adults and a child

Subject and samplea	IgA1 protease-producing bacteria				IgA1 protease-inhibiting activity
	Organism	Estimated density in undiluted secretion (CFU ml−1)b	% of total flora	IgA1 protease activity in vitro (C50)c	In nasal wash (CI50 titer)	Relative to total Ig conc (CI50 titer μg−1 ml)	Estimated for undiluted secretion (CI50 titer)d
A3,1	S. pneumoniae	2.1 × 103	0.2	410 (275–5,066)	4.2	0.18	97.5
B3,1	S. mitis biovar 1	6.8 × 104	22.3	1,621 (5.2–2,093)	0.0	0	0
C3,1	H. influenzae	7.2 × 106	99.6	4,760 (52–12,830)	8.6	0.22	199
D3,1	H. influenzae	<1.5 × 104	<0.01	639 (52–12,830)	18.2	0.16	422
E3,1	S. mitis biovar 1	0e	0	1,519 (5.2–2,093)	0.0	0	0
G3,3	H. influenzae	>3 × 106	NDf	2,029 (52–12,830)	51.0	1.26	1,183
Iw,3	H. influenzae	>3 × 106	ND	5,120 (52–12,830)	10.4	1.58	241

^aDesignations are as in Table 2. 

^bCalculated as CFU per milliliter of wash × 23.2 because individual dilution factors for these samples were not available. 

^cC₅₀ titer of a stationary-phase liquid culture (range of previously recorded [40] C₅₀ titers for strains of the species). 

^dCalculated as CI₅₀ for nasal wash × 23.2. 

^eIgA1 protease-producing S. mitis biovar 1 was not detected in nasal wash but constituted 0.6% of the CFU in a swab corresponding to a filter paper sample. 

^fND, not determined.