Tetraethylammonium heptadecafluorooctanesulphonate

Immunotoxicity

Administrative data

Endpoint:

immunotoxicity: short-term oral

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: well documented and scientifically acceptable

Data source

Reference

Reference Type:

publication

Title:

Gestational exposure to perfluorooctane sulfonate suppresses immune function in B6C3F1 mice

Author:

Keil DE, Mehlmann T, Butterworth L, Peden-Adams MM

Year:

2008

Bibliographic source:

Toxicol Sci 103, 77-85

Materials and methods

Principles of method if other than guideline:

Using the pairing of female C57BL/6N mice with male C3H/HeJ, developmental immunotoxicity was evaluated in B6C3F1 pups following oral maternal exposure to PFOS on gestations days (GD) 1-17. Exposure levels included 0.1, 1 and 5 mg/kg/day PFOS. Natural killer (NK) cell activity, SRBC IgM plaque assay, CD4/8 lymphocytic subpopulations, nitrite production in peritoneal macrophages, and body/organ weights were evaluated at 4 and 8 weeks of age in F1 pups.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Potassium heptadecafluorooctane-1-sulphonate

EC Number:

220-527-1

EC Name:

Potassium heptadecafluorooctane-1-sulphonate

Cas Number:

2795-39-3

IUPAC Name:

potassium 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluorooctane-1-sulfonate

Details on test material:

Perfluorooctane sulfonate (PFOS, potassium salt; 91% pure) was obtained from Fluka Chemical (Sigma-Aldrich, Switzerland).

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

male/female

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: 0.5% Tween 20

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

Dams were dosed until day 17 of gestation

Frequency of treatment:

daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0.1, 1 or 5 mg/kg/day
Basis:
nominal conc.

No. of animals per sex per dose:

There were 10-12 plug positive females assigned to each treatment group; only litters with 6-9 pups were maintained and were kept with their birth mother following the first 3 weeks of birth. For the immunotoxicity studies, groups were compromised of one female or male from each litter.

Control animals:

not specified

Results and discussion

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

0.1 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: pubs

2

Dose descriptor:

LOAEL

Effect level:

1 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: pubs

Any other information on results incl. tables

Body and Organ Mass and Immune Organ Cellularity

Body mass of male and female pups exposed to PFOS in utero was not significantly different from controls at either 4 or 8 weeks of age. Furthermore, pregnant dams did not experience any significant weight loss due to PFOS exposure (data not shown). In female pups at 4 weeks of age, liver mass was significantly decreased at the 0.1 mg/kg/day treatment and kidney mass was increased at the 5 mg/kg/day treatment, while spleen and thymus mass were not altered. In 4-week male pups spleen, thymus and kidney mass were not altered, but liver mass was significantly increased compared to control at the 5 mg/kg/day treatment level. In 8-week pups no alterations compared to control were noted in spleen, thymus, kidney, or liver mass regardless of gender. Additionally, splenic and

thymic cellularities were not altered compared to control at either 4 or 8 weeks of age in either gender.

NK-Cell Function and Plaque-Forming Cell (PFC) Assessments

NK-cell activity was assessed at both 4 and 8 weeks of age. There was no statistical interaction related to gender in the 4-week old pups; therefore, genders were combined for analysis. NK-cell activity was not altered compared to control in the 4-week old pups. At 8 weeks of age, however, differences in gender by treatment were noted and data were separated by gender for analysis. NK-cell activity was suppressed in 8-week old male offspring at the 1 and 5 mg/kg/day treatments (42.5% and 32.1% decrease, respectively) and was suppressed in female offspring at the 5 mg/kg/day treatment (35.1% decrease). The PFC response for SRBC-specific IgM production by B-cells was only assessed in the F1 adults (8 weeks of age). Differences in response by gender were observed, therefore, these data are presented with gender separated. In males, this response was significantly suppressed 53% in the 5 mg/kg/day exposure group, but it was not altered in the females.

Lymphocyte Immunophenotypes

Splenic or thymic lymphocyte subpopulations (B220+, CD3+, CD4+, CD8+, CD4-CD8- [DN], CD4+CD8+ [DP]) were assessed in pups at 4 and 8 weeks of age. Due to statistical interactions, genders were analyzed separately. Absolute numbers of splenic B220+ cells were significantly decreased by 21% in 4-week old female pups exposed to 5.0 mg/kg/day in utero while male pups remain unaffected (Table 3). By the adult age of 8 weeks, however, no significant changes in B220 labeled splenocytes were detected in either female or males for any of the treatments (data not shown). Absolute numbers of splenic or thymic CD8+, DP, and DN cells were not significantly altered at either age or gender (Table 3 and 4). In 4-week old pups, CD3+ or CD4+ cells were not significantly affected in either males or females. In 8- week old pups, the only significant differences detected were in male mice with a 25% decrease in CD3+ and 28% decrease in CD4+ thymocytes at the highest treatment level (Table 4). The thymocyte CD4:8 ratio was reduced from 4.2 in controls to 3.5 in the 5.0 mg/kg/day maternal dose group.

Nitrite Production by Peritoneal Macrophages

Peritoneal macrophage nitric oxide was assessed in F1 mice at 8 weeks of age only. It was not statistically altered in male or female offspring exposed to 5 mg/kg/day in utero. Furthermore, no difference in peritoneal cellularity was noted.

Applicant's summary and conclusion

Executive summary:

Using the pairing of female C57BL/6N mice with male C3H/HeJ, developmental immunotoxicity was evaluated in B6C3F1 pups following oral maternal exposure to PFOS on gestations days (GD) 1-17. Exposure levels included 0.1, 1 and 5 mg/kg/day PFOS. Natural killer (NK) cell activity, SRBC IgM plaque assay, CD4/8 lymphocytic subpopulations, nitrite production in peritoneal macrophages, and body/organ weights were evaluated at 4 and 8 weeks of age in F1 pups. No significant dose-responsive changes in maternal or pup body weights, flow cytometry, or macrophage function were observed, yet hepatomegaly was indicated in F1 male pups at 4 weeks of age. Functional deficits were not evident until 8 weeks of age when NK cell function and IgM production were significantly decreased. When compared to females, male pups were more sensitive to the effects of PFOS thereby establishing a no observed adverse effect level (NOAEL) and low observed adverse effect level (LOAEL) of 0.1 and 1.0 mg/kg/day (males only) following maternal PFOS exposure level, respectively. This study establishes that the developing immune system is sensitive to the effects of PFOS and results in functional deficits in innate and humoral immunity detectable at adulthood.