Sodium O-isobutyl dithiocarbonate

Immunotoxicity

Description of key information

There are conclusive but not suffcient data for the classification of substance Sodium isobutyl xanthate with regard to Immunotoxicity.

Key value for chemical safety assessment

Effect on immunotoxicity: via oral route

Link to relevant study records

Reference

Endpoint:

immunotoxicity: acute oral

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Well documented publication, acceptable for assessment. Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. Sodium isobutyl xanthate readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of sodium isobutyl xanthate.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Female mice were trated by gavage with three different dose of CS2 for 5 days. Some immunological parameters were tested.

GLP compliance:

not specified

Limit test:

no

Species:

mouse

Strain:

B6C3F1

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: obtained through National's Cancer Institute's animal program
- Age at study initiation: 8-10 weeks
- Weight at study initiation: 17-22 g
- Acclimation period: at least 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22-26
- Humidity (%): 40-60
- Photoperiod (hrs dark / hrs light): 12

Route of administration:

oral: gavage

Vehicle:

other: aqueous solution of 0.5% methylcellulose and 0.1% Tween 80

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

5 d

Frequency of treatment:

daily

Remarks:

Doses / Concentrations:
138, 551, 1102 mg/kg bw
Basis:
nominal conc.

No. of animals per sex per dose:

4

Control animals:

yes, concurrent vehicle

Observations and clinical examinations performed and frequency:

BODY WEIGHT: Yes

ORGAN WEIGHT: thymus and spleen were weighed at the end of the experiment

HEMATOLOGY: Blood samples were taken on day 6

Non-specific cell-mediated immunity:

WHITE CELLS
White cell counts were recorded with a Coulter model Zf electronic cell counter and differentials were done using-dried smears of whole blood samples stained with Wright's stain.

NATURAL KILLER (NK) CELL ACTIVITY: Yes
- Method: measurement of lysis of 51Cr-labeled YAC-1 tumor cells by splenocytes in complete RPMI 1640 medium supplemented with 10% FCS (Duke et al., 1985)

THYMOCYTES
The lymphocytes were counted in the thymus with the use of fluorescent-labeled monoclonal antibodies, after removal of the thymus. The procedure is described in the publication as follows: 'A single-cell suspension was prepared from each thymus and adjusted to 2 × 106 cells/ml in HBSS with 0.2% bovine serum albumin (BSA) and 0.1% sodium azide. One hundred microliters of this cell suspension and a mixture of fluoresce in labeled anti-CD8 and phycoerythrin-labeled anti-CD4 (Gibco/BRL, Grand Island, NY) were transferred into a 96-well u -bottom microtiter plate. The cells were incubated for 30 min at 4°C and centrifuged at 400 × g for 5 min. The supernatant was aspirated, 150 μl of preheated red blood cell (RBC) lysis buffer (37°C) was added, and this mixture was incubated for 5 min at 37°C. Erythrocyte lysis buffer was prepared by combining 4.13 g NH4Cl, 0.5 g NaHCO3, and 0.03 g EDTA in 500 ml of tissue-culture-grade water and adjusting the pH to 7.0. The cells were centrifuged, washed one time with HBSS with BSA and azide, and stored in the dark at 4°C. Within 1 h, the cells were analyzed using a flow cytometer (Facstar, Becton-Dickinson). The total number of nucleated cells per thymus was determined using a Coulter model Zf electronic cell counter, and the absolute number of cells in each subpopulation was determined by multiplying the fraction of cells in each subpopulation by the total number of cells in the thymus.'

Statistics:

One-way analysis of variance, Dunnett's t-test

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Gross pathological findings:

not specified

Details on results:

MORTALITY 2/5 animals died after administration of 1102 mg/kg bw

BODY WEIGHT: decreased by less than 10%, except for the highest dose were it was more than 10%

Dose descriptor:

NOAEL

Effect level:

138 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

other: No significant changes in thymus weight, in white blood cells differentials, in spleen weight, and in NK cell activity.

CS2 exposure did not result in any significant effect on the immunological parameters that were investigated in this study, except for thymus weight and thymus cellularity. CS2 administration of 137.8 mg/kg bw increased thymus cellularity by 57%, while treatment with 1102.4 mg/kg bw resulted in decreased thymus weight by 48%. However, this high dose exerted overt toxicity in the mice and hence, it is probable that the immunological effects are secondary, due to failure of homeostasis in other organ systems and might not reflect direct immunotoxicity of the compound. The dose of 551.2 mg/kg bw caused no significant changes in thymus weight. No significant alterations were measured in the white blod cells differentials, in spleen weight, and in NK cell activity.

Conclusions:

In the present investigation CS2 challenge of female mice by gavage did not result in any specific immunotoxic effects. However, the immunological parameters tested are limited.
Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. Sodium isobutyl xanthate readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of sodium isobutyl xanthate.

Executive summary:

Female mice B6C3F1 were challenged with carbon disulfide by gavage. The following doses were administered daily for 5 consecutive days: 138, 551, 1102 mg/kg bw. Mortality, changes in body weights, in thymus and spleen weights, in white cell counts, in thymocytes, as well as in NK cell activity were recorded. CS2 exposure did not exhibit any significant effect on the immunological parameters recorded, except for thymus weight and cellularity. CS2 administration of 137.8 mg/kg bw increased thymus cellularity by 57%, while treatment with 1102.4 mg/kg bw resulted in decreased thymus weight by 48%. However, this high dose exerted overt toxicity in the mice and hence, it is probable that the immunological are secondary, due to failure of homeostasis in other organ. systems and might not reflect specific immunotoxic effects of the compound. The dose of 551.2 mg/kg bw caused no significant changes in thymus weight. No significant alterations were measured in the white blod cells differentials, in spleen weight, and in NK cell activity.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

138 mg/kg bw/day

Study duration:

subacute

Species:

mouse

Effect on immunotoxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

immunotoxicity: acute oral

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Well documented publication, acceptable for assessment. Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. Sodium isobutyl xanthate readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of sodium isobutyl xanthate.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Female mice were trated by gavage with three different dose of CS2 for 5 days. Some immunological parameters were tested.

GLP compliance:

not specified

Limit test:

no

Species:

mouse

Strain:

B6C3F1

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: obtained through National's Cancer Institute's animal program
- Age at study initiation: 8-10 weeks
- Weight at study initiation: 17-22 g
- Acclimation period: at least 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22-26
- Humidity (%): 40-60
- Photoperiod (hrs dark / hrs light): 12

Route of administration:

oral: gavage

Vehicle:

other: aqueous solution of 0.5% methylcellulose and 0.1% Tween 80

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

5 d

Frequency of treatment:

daily

Remarks:

Doses / Concentrations:
138, 551, 1102 mg/kg bw
Basis:
nominal conc.

No. of animals per sex per dose:

4

Control animals:

yes, concurrent vehicle

Observations and clinical examinations performed and frequency:

BODY WEIGHT: Yes

ORGAN WEIGHT: thymus and spleen were weighed at the end of the experiment

HEMATOLOGY: Blood samples were taken on day 6

Non-specific cell-mediated immunity:

WHITE CELLS
White cell counts were recorded with a Coulter model Zf electronic cell counter and differentials were done using-dried smears of whole blood samples stained with Wright's stain.

NATURAL KILLER (NK) CELL ACTIVITY: Yes
- Method: measurement of lysis of 51Cr-labeled YAC-1 tumor cells by splenocytes in complete RPMI 1640 medium supplemented with 10% FCS (Duke et al., 1985)

THYMOCYTES
The lymphocytes were counted in the thymus with the use of fluorescent-labeled monoclonal antibodies, after removal of the thymus. The procedure is described in the publication as follows: 'A single-cell suspension was prepared from each thymus and adjusted to 2 × 106 cells/ml in HBSS with 0.2% bovine serum albumin (BSA) and 0.1% sodium azide. One hundred microliters of this cell suspension and a mixture of fluoresce in labeled anti-CD8 and phycoerythrin-labeled anti-CD4 (Gibco/BRL, Grand Island, NY) were transferred into a 96-well u -bottom microtiter plate. The cells were incubated for 30 min at 4°C and centrifuged at 400 × g for 5 min. The supernatant was aspirated, 150 μl of preheated red blood cell (RBC) lysis buffer (37°C) was added, and this mixture was incubated for 5 min at 37°C. Erythrocyte lysis buffer was prepared by combining 4.13 g NH4Cl, 0.5 g NaHCO3, and 0.03 g EDTA in 500 ml of tissue-culture-grade water and adjusting the pH to 7.0. The cells were centrifuged, washed one time with HBSS with BSA and azide, and stored in the dark at 4°C. Within 1 h, the cells were analyzed using a flow cytometer (Facstar, Becton-Dickinson). The total number of nucleated cells per thymus was determined using a Coulter model Zf electronic cell counter, and the absolute number of cells in each subpopulation was determined by multiplying the fraction of cells in each subpopulation by the total number of cells in the thymus.'

Statistics:

One-way analysis of variance, Dunnett's t-test

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Gross pathological findings:

not specified

Details on results:

MORTALITY 2/5 animals died after administration of 1102 mg/kg bw

BODY WEIGHT: decreased by less than 10%, except for the highest dose were it was more than 10%

Dose descriptor:

NOAEL

Effect level:

138 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

other: No significant changes in thymus weight, in white blood cells differentials, in spleen weight, and in NK cell activity.

CS2 exposure did not result in any significant effect on the immunological parameters that were investigated in this study, except for thymus weight and thymus cellularity. CS2 administration of 137.8 mg/kg bw increased thymus cellularity by 57%, while treatment with 1102.4 mg/kg bw resulted in decreased thymus weight by 48%. However, this high dose exerted overt toxicity in the mice and hence, it is probable that the immunological effects are secondary, due to failure of homeostasis in other organ systems and might not reflect direct immunotoxicity of the compound. The dose of 551.2 mg/kg bw caused no significant changes in thymus weight. No significant alterations were measured in the white blod cells differentials, in spleen weight, and in NK cell activity.

Conclusions:

In the present investigation CS2 challenge of female mice by gavage did not result in any specific immunotoxic effects. However, the immunological parameters tested are limited.
Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. Sodium isobutyl xanthate readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of sodium isobutyl xanthate.

Executive summary:

Female mice B6C3F1 were challenged with carbon disulfide by gavage. The following doses were administered daily for 5 consecutive days: 138, 551, 1102 mg/kg bw. Mortality, changes in body weights, in thymus and spleen weights, in white cell counts, in thymocytes, as well as in NK cell activity were recorded. CS2 exposure did not exhibit any significant effect on the immunological parameters recorded, except for thymus weight and cellularity. CS2 administration of 137.8 mg/kg bw increased thymus cellularity by 57%, while treatment with 1102.4 mg/kg bw resulted in decreased thymus weight by 48%. However, this high dose exerted overt toxicity in the mice and hence, it is probable that the immunological are secondary, due to failure of homeostasis in other organ. systems and might not reflect specific immunotoxic effects of the compound. The dose of 551.2 mg/kg bw caused no significant changes in thymus weight. No significant alterations were measured in the white blod cells differentials, in spleen weight, and in NK cell activity.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

6 mg/m³

Study duration:

subacute

Species:

mouse

Effect on immunotoxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

immunotoxicity: acute oral

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Well documented publication, acceptable for assessment. Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. Sodium isobutyl xanthate readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of sodium isobutyl xanthate.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Female mice were trated by gavage with three different dose of CS2 for 5 days. Some immunological parameters were tested.

GLP compliance:

not specified

Limit test:

no

Species:

mouse

Strain:

B6C3F1

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: obtained through National's Cancer Institute's animal program
- Age at study initiation: 8-10 weeks
- Weight at study initiation: 17-22 g
- Acclimation period: at least 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22-26
- Humidity (%): 40-60
- Photoperiod (hrs dark / hrs light): 12

Route of administration:

oral: gavage

Vehicle:

other: aqueous solution of 0.5% methylcellulose and 0.1% Tween 80

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

5 d

Frequency of treatment:

daily

Remarks:

Doses / Concentrations:
138, 551, 1102 mg/kg bw
Basis:
nominal conc.

No. of animals per sex per dose:

4

Control animals:

yes, concurrent vehicle

Observations and clinical examinations performed and frequency:

BODY WEIGHT: Yes

ORGAN WEIGHT: thymus and spleen were weighed at the end of the experiment

HEMATOLOGY: Blood samples were taken on day 6

Non-specific cell-mediated immunity:

WHITE CELLS
White cell counts were recorded with a Coulter model Zf electronic cell counter and differentials were done using-dried smears of whole blood samples stained with Wright's stain.

NATURAL KILLER (NK) CELL ACTIVITY: Yes
- Method: measurement of lysis of 51Cr-labeled YAC-1 tumor cells by splenocytes in complete RPMI 1640 medium supplemented with 10% FCS (Duke et al., 1985)

THYMOCYTES
The lymphocytes were counted in the thymus with the use of fluorescent-labeled monoclonal antibodies, after removal of the thymus. The procedure is described in the publication as follows: 'A single-cell suspension was prepared from each thymus and adjusted to 2 × 106 cells/ml in HBSS with 0.2% bovine serum albumin (BSA) and 0.1% sodium azide. One hundred microliters of this cell suspension and a mixture of fluoresce in labeled anti-CD8 and phycoerythrin-labeled anti-CD4 (Gibco/BRL, Grand Island, NY) were transferred into a 96-well u -bottom microtiter plate. The cells were incubated for 30 min at 4°C and centrifuged at 400 × g for 5 min. The supernatant was aspirated, 150 μl of preheated red blood cell (RBC) lysis buffer (37°C) was added, and this mixture was incubated for 5 min at 37°C. Erythrocyte lysis buffer was prepared by combining 4.13 g NH4Cl, 0.5 g NaHCO3, and 0.03 g EDTA in 500 ml of tissue-culture-grade water and adjusting the pH to 7.0. The cells were centrifuged, washed one time with HBSS with BSA and azide, and stored in the dark at 4°C. Within 1 h, the cells were analyzed using a flow cytometer (Facstar, Becton-Dickinson). The total number of nucleated cells per thymus was determined using a Coulter model Zf electronic cell counter, and the absolute number of cells in each subpopulation was determined by multiplying the fraction of cells in each subpopulation by the total number of cells in the thymus.'

Statistics:

One-way analysis of variance, Dunnett's t-test

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Gross pathological findings:

not specified

Details on results:

MORTALITY 2/5 animals died after administration of 1102 mg/kg bw

BODY WEIGHT: decreased by less than 10%, except for the highest dose were it was more than 10%

Dose descriptor:

NOAEL

Effect level:

138 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

other: No significant changes in thymus weight, in white blood cells differentials, in spleen weight, and in NK cell activity.

CS2 exposure did not result in any significant effect on the immunological parameters that were investigated in this study, except for thymus weight and thymus cellularity. CS2 administration of 137.8 mg/kg bw increased thymus cellularity by 57%, while treatment with 1102.4 mg/kg bw resulted in decreased thymus weight by 48%. However, this high dose exerted overt toxicity in the mice and hence, it is probable that the immunological effects are secondary, due to failure of homeostasis in other organ systems and might not reflect direct immunotoxicity of the compound. The dose of 551.2 mg/kg bw caused no significant changes in thymus weight. No significant alterations were measured in the white blod cells differentials, in spleen weight, and in NK cell activity.

Conclusions:

In the present investigation CS2 challenge of female mice by gavage did not result in any specific immunotoxic effects. However, the immunological parameters tested are limited.
Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. Sodium isobutyl xanthate readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of sodium isobutyl xanthate.

Executive summary:

Female mice B6C3F1 were challenged with carbon disulfide by gavage. The following doses were administered daily for 5 consecutive days: 138, 551, 1102 mg/kg bw. Mortality, changes in body weights, in thymus and spleen weights, in white cell counts, in thymocytes, as well as in NK cell activity were recorded. CS2 exposure did not exhibit any significant effect on the immunological parameters recorded, except for thymus weight and cellularity. CS2 administration of 137.8 mg/kg bw increased thymus cellularity by 57%, while treatment with 1102.4 mg/kg bw resulted in decreased thymus weight by 48%. However, this high dose exerted overt toxicity in the mice and hence, it is probable that the immunological are secondary, due to failure of homeostasis in other organ. systems and might not reflect specific immunotoxic effects of the compound. The dose of 551.2 mg/kg bw caused no significant changes in thymus weight. No significant alterations were measured in the white blod cells differentials, in spleen weight, and in NK cell activity.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1.1 mg/kg bw/day

Study duration:

subacute

Species:

mouse

Additional information

Oral exposure:

Female mice B6C3F1 were challenged with carbon disulfide by gavage. The following doses were administered daily for 5 consecutive days: 138, 551, 1102 mg/kg bw.In thestudy of, et al 1996 , investigation CS2 challenge of female mice by gavage did not result in any specific immunotoxic effects.

The NOAEL was 138 mg/kg/bw based on no significant changes in thymus weight, in white blood cells differentials, in spleen weight, and in NK cell activity.

Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. Sodium isobutyl xanthate readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of sodium isobutyl xanthate.

 

Dermal exposure:

For dermal exposure we taken that:

-the average weight of mice is 80g (60 -100g),

-the dose is applied over an area which is approximately 10% of the total body surface=0.008 kg

 corrected dermal NOAEL=   oral NOAEL

138 mg/kg bw/day x 0.008 kg =                  

 NOAELmice  = 1.1 mg/kg bw/day

 

Inhalation exposure:

The oral dose for the rat is converted to the corresponding air concentration using a standard breathing volume for the rat (1.15 m3/kg for 24 hours exposure. The resulting air concentration needs to be additionally corrected for 24 hlight activity (20 m³), assuming 100 % absorption for both routes.

NOAEL mice     =  138 mg/kg bw/day

÷1.15 m3/kgbw

÷20m3/mice

NOAECmice  = 6 mg/m3

Justification for classification or non-classification

There are conclusive but not suffcient data for the classification of substance Sodium isobutyl xanthate with regard to Immunotoxicity.