Jet Fuel Kerosene is not Immunosuppressive in Mice or Rats Following Inhalation for 28 Days

Figures & data

TABLE 1. Eleven Component Vapor Phase Analysis for the Mouse Exposure Atmospheres

	Area Percent for:
Exposure	Octane	Nonane	Decane	Undecane	Dodecane	Tridecane
500 mg/m^3	0.94 ± 0.056	3.5 ± 0.18	6.8 ± 0.25	8.4 ± 0.21	5.7 ± 0.22	3.2 ± 0.20
1000 mg/m^3	1.1 ± 0.033	3.7 ± 0.66	7.2 ± 0.13	8.9 ± 0.25	5.8 ± 0.18	2.9 ± 0.073
2000 mg/m^3	1.5 ± 0.15	5.1 ± 0.55	8.5 ± 0.38	8.4 ± 0.32	4.1 ± 0.39	1.6 ± 0.22
	Area Percent for:
Exposure	Tetradecane	Pentadecane	Hexadecane	Heptadecane	Naphthalene
500 mg/m^3	1.1 ± 0.12	0.36 ± 0.16	<MDL ± NA	<MDL ± NA	<MDL ± NA
1000 mg/m^3	0.83 ± 0.31	0.15 ± 0.050	<MDL ± NA	<MDL ± NA	<MDL ± NA
2000 mg/m^3	0.35 ± 0.18	0.050 ± NA	<MDL ± NA	<MDL ± NA	<MDL ± NA
Results represent the mean ± SD, n = 6. <MDL-below minimum detection level, NA-not applicable.

TABLE 2. Eleven Component Vapor Phase Analysis for the Rat Exposure Atmospheres

	Area Percent for:
Exposure	Octane	Nonane	Decane	Undecane	Dodecane	Tridecane
500 mg/m^3	0.94 ± 0.16	3.7 ± 0.49	6.7 ± 0.32	7.7 ± 0.35	5.4 ± 0.44	3.3 ± 0.22
1000 mg/m^3	1.1 ± 0.034	3.8 ± 0.11	7.2 ± 0.16	8.7 ± 0.17	5.4 ± 0.17	2.6 ± 0.083
2000 mg/m^3	1.1 ± 0.079	4.0 ± 0.22	7.3 ± 0.22	8.4 ± 0.11	4.9 ± 0.24	2.3 ± 0.17
	Area Percent for:
Exposure	Tetradecane	Pentadecane	hexadecane	Heptadecane	Napthalene
500 mg/m^3	1.3 ± 0.13	0.23 ± 0.050	0.051 ± NA	<MDL ± NA	<MDL ± NA
1000 mg/m^3	0.56 ± 0.11	0.15 ± NA	<MDL ± NA	<MDL ± NA	<MDL ± NA
2000 mg/m^3	0.68 ± 0.12	0.15 ± NA	<MDL ± NA	<MDL ± NA	<MDL ± NA
Results represent the mean ± SD, n = 5–6. <MDL-below minimum detection level, NA-not applicable.

TABLE 3. Terminal body weights, spleen weights, and thymus weights of female B6C3F1 mice and female Crl:CD® rats exposed to Jet Fuel Kerosene by inhalation for 28 days

			Jet Fuel Kerosene (mg/m^3)
Parameter	Control Unrestrained	Control Nose Cone Air Only	500	1000	2000	CPS 50 mg/kg (mice) 25 mg/kg (rats)	H/NH	Trend Analysis
Mice
Body Wgt (g)	24.6 ± 0.3*	23.0 ± 0.4	23.6 ± 0.3	23.3 ± 0.3	23.5 ± 0.3	22.5 ± 0.5	H	NS
Spleen (mg)	116 ± 5	124 ± 4	139 ± 10	136 ± 12	126 ± 6	93 ± 6*	NH	NS
% Body Wgt	0.471 ± 0.016*	0.539 ± 0.016	0.588 ± 0.041	0.583 ± 0.053	0.536 ± 0.024	0.414 ± 0.026*	NH	NS
Thymus (mg)	55.1 ± 2.3*	40.9 ± 2.1	42.1 ± 3.2	44.3 ± 4.1	44.5 ± 3.3	27.0 ± 2.3*	H	NS
% Body Wgt	0.226 ± 0.009*	0.177 ± 0.009	0.177 ± 0.013	0.189 ± 0.017	0.189 ± 0.013	0.121 ± 0.011*	H	NS
Rats
Body Wgt (g)	NA	254.1 ± 4.5	252.3 ± 7.6	240.4 ± 6.6	239.1 ± 5.7	251 ± 9.0	H	p ≤ 0.05
Spleen (mg)	NA	556 ± 21	544 ± 33	489 ± 21	529 ± 25	310 ± 19*	H	NS
% Body Wgt	NA	0.22 ± 0.01	0.22 ± 0.01	0.20 ± 0.01	0.22 ± 0.01	0.12 ± 0.01*	NH	NS
Thymus (mg)	NA	390 ± 19	390 ± 26	415 ± 29	328 ± 24	159 ± 19*	H	NS
% Body Wgt	NA	0.15 ± 0.01	0.16 ± 0.01	0.17 ± 0.01	0.14 ± 0.01	0.06 ± 0.01*	H	NS
Values represent the mean ± SE derived from 9 or 10 animals per group; *p ≤ 0.05 compared to the control nose cone air only group; H = homogeneous data; NH = non-homogeneous data; NS = not significant; NA = not applicable.

TABLE 4. Spleen cell phenotypes in female B6C3F1 mice exposed to Jet Fuel Kerosene by inhalation for 28 days

Exposure	Spleen Cells	Ig^+a	CD3^+b	CD3^+CD4^+c	CD3^+CD8^+d	NK1.1^+CD8^−e	Mac-3^+f
Absolute Values (× 10^6)
Control (Unrestrained)	124.3 ± 7.7*	38.03 ± 3.41*	20.26 ± 2.16*	12.18 ± 1.26*	6.09 ± 0.76*	2.63 ± 0.24*	4.71 ± 0.54
Control (Nose Cone)	94.0 ± 9.7	21.98 ± 1.92	12.54 ± 1.08	7.04 ± 0.56	3.80 ± 0.33	1.60 ± 0.17	4.10 ± 0.73
Jet Fuel Kerosene
500 mg/m^3	118.5 ± 9.5	24.95 ± 0.86	13.35 ± 0.67	7.40 ± 0.34	4.22 ± 0.22	2.16 ± 0.15*	5.55 ± 0.67
1000 mg/m^3	123.0 ± 4.7	24.19 ± 1.82	12.18 ± 1.08	6.99 ± 0.66	3.78 ± 0.31	2.11 ± 0.10*	5.22 ± 0.32
2000 mg/m^3	106.1 ± 3.8	20.50 ± 0.78	11.39 ± 0.55	5.94 ± 0.30	3.64 ± 0.20	1.98 ± 0.09	5.20 ± 0.35
CPS (50 mg/kg)	49.9 ± 2.9*	8.08 ± 0.68*	11.02 ± 1.12	6.29 ± 0.63	3.76 ± 0.41	NA	2.34 ± 0.16*
AAGM1 (1:10)	127.2 ± 2.8*	NA	NA	NA	NA	1.31 ± 0.08	NA
H/NH	NH	NH	H	H	H	NH	NH
Trend Analysis	NS	NS	NS	p ≤ 0.05	NS	NS	NS
Percent Values
Control (Unrestrained)		30.27 ± 1.25*	16.02 ± 0.95	9.68 ± 0.59	4.79 ± 0.37	2.11 ± 0.12*	3.76 ± 0.40
Control (Nose Cone)		23.99 ± 1.27	13.99 ± 1.09	7.90 ± 0.62	4.22 ± 0.31	1.70 ± 0.09	4.23 ± 0.46
Jet Fuel Kerosene
500 mg/m^3		21.96 ± 1.66	11.72 ± 0.96	6.46 ± 0.47	3.68 ± 0.28	1.87 ± 0.13	4.63 ± 0.28
1000 mg/m^3		20.07 ± 1.89	10.17 ± 1.14	5.84 ± 0.69*	3.15 ± 0.33	1.75 ± 0.12	4.29 ± 0.31
2000 mg/m^3		19.52 ± 0.96	10.90 ± 0.76	5.70 ± 0.43*	3.48 ± 0.25	1.88 ± 0.10	4.88 ± 0.24
CPS (50 mg/kg)		16.04 ± 0.74*	21.89 ± 1.61*	12.51 ± 0.93*	7.43 ± 0.59*	NA	4.76 ± 0.28
AAGM1 (1:10)		NA	NA	NA	NA	1.03 ± 0.06*	NA
H/NH		H	H	H	H	H	H
Trend Analysis		p ≤ 0.05	p ≤ 0.05	p ≤ 0.05	p ≤ 0.05	NS	NS
^aB-lymphocyte; ^bT-lymphocyte; ^cHelper T-lymphocyte; ^dCytotoxic T-lymphocyte; ^eNatural Killer cell; ^fMacrophage; Values represent the mean ± SE derived from 9 or 10 animals per group; *p ≤ 0.05 compared to the control nose cone air only group H = homogeneous data; NH = non-homogeneous data; NS = not significant; NA = not applicable.

TABLE 5. Spleen cell phenotypes in female Crl:CD® rats exposed to Jet Fuel Kerosene by inhalation for 28 days

Exposure	Spleen Cells	CD45RA^+a	CD5^+b	CD4+CD5^+c	CD8+CD5^+d	NKRP1A+CD8^−e	His36^+f
Absolute Values (× 10^6)
Control	561.8 ± 21.1	382.1 ± 19.1	121.4 ± 10.1	77.7 ± 5.4	50.7 ± 5.3	31.1 ± 1.8	60.1 ± 6.7
Jet Fuel Kerosene
500 mg/m^3	534.4 ± 34.8	376.2 ± 29.2	111.2 ± 11.0	74.8 ± 6.8	44.0 ± 5.9	29.9 ± 2.6	62.1 ± 5.7
1000 mg/m^3	461.9 ± 21.1*	300.8 ± 17.6*	117.3 ± 7.3	74.9 ± 5.5	47.3 ± 3.1	32.9 ± 3.3	69.1 ± 9.0
2000 mg/m^3	479.9 ± 21.5	323.3 ± 17.5	109.1 ± 9.3	74.9 ± 5.6	41.1 ± 3.7	27.4 ± 3.4	64.5 ± 6.7
CPS (25 mg/kg)	144.5 ± 11.3*	12.2 ± 2.4*	105.1 ± 9.1	56.8 ± 5.3*	54.3 ± 5.3	NA	9.8 ± 3.2*
AAGM1 (1:10)	517.0 ± 27.0	NA	NA	NA	NA	5.1 ± 0.7*	NA
H/NH	H	H	H	H	H	H	H
Trend Analysis	p ≤ 0.01	p ≤ 0.01	NS	NS	NS	NS	NS
Percent Values
Control		68.04 ± 2.24	21.61 ± 1.63	13.86 ± 0.88	8.97 ± 0.82	5.61 ± 0.44	10.73 ± 1.18
Jet Fuel Kerosene
500 mg/m^3		70.05 ± 1.82	20.75 ± 1.36	14.13 ± 1.01	8.06 ± 0.73	5.70 ± 0.52	12.25 ± 1.61
1000 mg/m^3		64.83 ± 1.41	25.38 ± 1.07	16.23 ± 0.89	10.28 ± 0.58	7.31 ± 0.87	14.83 ± 1.66
2000 mg/m^3		67.40 ± 2.13	22.71 ± 1.73	15.69 ± 1.13	8.62 ± 0.77	5.69 ± 0.69	13.37 ± 1.21
CPS (25 mg/kg)		8.34 ± 1.63*	72.55 ± 2.29*	39.02 ± 1.48*	37.51 ± 2.08*	NA	6.43 ± 1.63*
AAGM1 (1:10)		NA	NA	NA	NA	0.98 ± 0.11**	NA
H/NH		H	H	H	H	H	H
Trend Analysis		NS	NS	NS	NS	NS	p ≤ 0.05
^aB-lymphocyte; ^bT-lymphocyte; ^cHelper T-lymphocyte; ^dCytotoxic T-lymphocyte; ^eNatural Killer cell; ^fMacrophage; Values represent the mean ± SE derived from 9 or 10 animals per group; *p ≤ 0.05 compared to the control nose cone air only group H = homogeneous data; NH = non-homogeneous data; NS = not significant; NA = not applicable.

FIGURE 1. AFC response to sRBC in female B6C3F1 mice exposed to jet fuel kerosene for 28 d. On d 25 of the study, mice were immunized with 7.5 × 10⁷ sRBC by iv injection. Positive control mice received 50 mg/kg CPS daily by ip injection for 4 d prior to study termination on d 29. Left panel: AFC specific activity (IgM AFC/10⁶ splenocytes); right panel: AFC total Spleen activity (IgM AFC/Spleen). Asterisk indicates statistically significant differences from control: *p ≤ .05.

FIGURE 2. AFC response to sRBC in female Crl:CD rats exposed to jet fuel kerosene for 28 d. On d 25 of the study, rats were immunized with 2 × 10⁸ sRBC by iv injection. Positive control animals received 25 mg/kg CPS daily by ip injection for 4 d prior to study termination on d 29. The top two panels present the mean + SE for each group, while the bottom two panels present the individual responses of each animal. Left panels: AFC specific activity (IgM AFC/10⁶ splenocytes); right panels: AFC total Spleen activity (IgM AFC/Spleen). Asterisk indicates statistically significant differences from control: *p ≤ .05.

FIGURE 3. Anti-CD3 mediated proliferation of splenocytes from female B6C3F1 mice and Crl:CD rats exposed to jet fuel kerosene for 28 d. Left panel: mice. Right panel: rats. CPS, the positive control, was administered by ip injection at either 25 mg/kg (rats) or 50 mg/kg (mice) daily on d 25–28. Spleens were harvested aseptically, and spleen cells were cultured in 96-well plates (uncoated or coated with anti-CD3 antibody) for 3 d. All cultures were labeled with [³H]thymidine (1 μCi/well) 18–24 h prior to harvest. Incorporation of [³H]thymidine into proliferating cells was the assay endpoint. Results are expressed as CPM/2 × 10⁵ splenocytes (mice) or as CPM/5 × 10⁵ splenocytes (rats). Asterisk indicates statistically significant differences from control: *p ≤ .05.

FIGURE 4. DTH response to C. albicans in female B6C3F1 mice and Crl:CD rats exposed to jet fuel kerosene for 28 d. Top panel: mice. Bottom panel: rats. Animals were immunized on exposure d 21 with formalin-fixed C. albicans organisms and challenged in the right footpad with chitosan antigen one d after the last inhalation exposure. Footpad swelling was determined 24 h postchallenge. Results are reported in terms of mm × 100. Asterisk indicates statistically significant differences from control: *p ≤ .05.

FIGURE 5. NK cell activity in female B6C3F1 mice exposed to jet fuel kerosene for 28 d. AAGM1, the positive control, was administered by iv injection 24 h prior to study termination. On d 29, spleens were harvested aseptically, and spleen cells were cultured with ⁵¹Cr-labeled YAC-1 target cells for 4 h. From each culture 100 μl of supernatant was counted in a gamma counter to assess the release of ⁵¹Cr from the target cells. Results are presented for three E:T ratios (200:1, 100:1, and 50:1) in terms of percent cytotoxicity, which was calculated as the difference between the experimental release and spontaneous release, divided by the difference between the maximum release and spontaneous release.