2,2'-iminodi(ethylamine)

Respiratory sensitisation

Administrative data

Endpoint:

respiratory sensitisation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Not applicable

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was not conducted according to guidelines but was conducted according to GLPs and the report contains sufficient data for interpretation of study results

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Respiratory sensitization potential was examined for a number of ethyleneamines using the cytokine fingerprinting assay with LLNA positive materials.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2,2'-iminodi(ethylamine)

EC Number:

203-865-4

EC Name:

2,2'-iminodi(ethylamine)

Cas Number:

111-40-0

Molecular formula:

C4H13N3

IUPAC Name:

bis(2-aminoethyl)amine

Details on test material:

- Name of test material (as cited in study report): Union Carbide Corporation (UCC) Number 17001849
- Physical state: Tranparent colorless liquid

Test animals

Species:

mouse

Strain:

Balb/c

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Seralab, Bicester, Oxfordshire,UK
- Age at study initiation: 6-12 weeks old
- Housing:Mice were housed in groups of 1, 4 or 5 in metal cages
- Diet: ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 +/- 2°C
- Humidity (%): 55 +/-10%
- Photoperiod (hrs dark / hrs light): 12 hour light/dark cycle.

Test system

Route of induction exposure:

dermal

Vehicle:

other: Acetone Olive Oil (AOO) or in water

Concentration:

10% TMA, or 1% DNCB or 10% DETA in AOO

No. of animals per dose:

Five

Details on study design:

Sensitization of mice for cytokine production
Groups of mice (n = 5) received 50 ml of various concentrations of test material freshly prepared in AOO or in water:AOO bilaterally on each shaved flank. Control animals were treated concurrently with 10% TMA, or 1% DNCB dissolved in AOO (n = 5), or vehicle alone (n = 10). Five days later this treatment was repeated. After a further 5 days, 25 ml of chemical or vehicle alone was applied to the dorsum of both ears daily for three consecutive days.

Preparation of cells from draining lymph nodes for cytokine expression
Thirteen days after the initiation of treatment, draining auricular lymph nodes were excised and pooled for each experimental group. A single cell suspension of LNC was prepared under aseptic conditions by gentle mechanical disaggregation through sterile 200-mesh stainless steel gauze. Viable cell counts were performed by exclusion of 0.5% trypan blue and LNC were cultured in RPMI-1640 growth medium (Gibco, Renfrewshire, UK) supplemented with 25 mM/L HEPES, 400 mg/ml streptomycin, 400 mg/ml ampicillin and 10% heat-inactivated fetal calf serum (RPMIFCS). Cells (1 ml aliquots) at 107 cells/ml were seeded into 24-well tissue culture plates and maintained at 37oC in a humidified atmosphere of 5% CO2 in air in the presence or absence of 2 mg/ml of concanavalin A (con A; Sigma). Culture was terminated after 18-120 hours, supernatants collected, centrifuged at 100 g for 5 min and stored at -70C prior to analysis.

The cytokine fingerprinting assays with the LLNA positive materials were conducted using test concentrations of the chemicals that were shown to be immunogenic in the LLNA. In each instance, responses provoked by test materials were compared with those elicited concurrently by the control
chemicals 2,4-dinitrochlorobenzene (DNCB) and trimellitic anhydride (TMA). The former is a potent contact allergen which lacks the ability to cause sensitization of the respiratory tract, while the latter is a known cause of respiratory allergy and occupational asthma in humans. Concentrations of
DNCB (1%) and TMA (10%) were used; these have been shown previously to induce equivalent levels of immune activation following topical exposure with respect to both lymphocyte proliferation and IgG antibody responses.

Challenge controls:

Not applicable.

Positive control substance(s):

trimellitic anhydride (TMA)

Negative control substance(s):

2,4-dinitrochlorobenzene (DNCB)

Results and discussion

Results:

Under conditions where DNCB and TMA stimulated the marked type 1 and type 2 cytokine expression patterns as described above, DETA elicited little or no detectable interleukins (IL)-4 or IL-10 and only very low levels of IFN-g secretion. Due to the irritant properties of this material, it was not possible to test at higher concentrations.

Positive control results:

The historical values for proliferation induced by TMA (10%) are stimulation indices of 26.1 +/- 3.5 (mean and SEs of 3 experiments).

Negative control results:

The historical values for proliferation induced by DNCB (1%) are stimulation indices of 24.2 +/- 3.5 (mean and SEs of 3 experiments).

Any other information on results incl. tables

Not applicable

Applicant's summary and conclusion

Conclusions:

It is not possible to confirm a secure negative with respect to respiratory sensitizing pote

Executive summary:

The purpose of these studies was to evaluate the allergenic potential and to determine the ability to cause allergic sensitization of the respiratory tract. To this end, a selective and step-wise approach was employed using the local lymph node assay (LLNA), cytokine fingerprinting, and the mouse IgE test. Chemicals that elicited positive responses in the LLNA test were selected for further analyses using cytokine fingerprinting to determine whether they provoke in mice patterns of cytokine production consistent with a potential to cause respiratory sensitization. The rationale is that experience to date indicates all chemical respiratory allergens are able to induce positive responses in the LLNA and in other predictive tests for contact sensitizing potential. The corollary is that chemicals which failed to cause LLNA responses lacked the ability to cause sensitization of the respiratory tract also. The mouse IgE test was used for the identification of chemicals that had the potential to cause allergic sensitization of the respiratory tract. The method was based upon the fact that topical exposure of mice to chemical respiratory allergens

elicits a substantial increase in the total serum concentration of IgE; a response not observed with chemical contact allergens believed not to cause respiratory sensitization.

DETA possesses contact allergic potential (positive in the local lymph node assay but failed to provoke significant cytokine production as judged by cytokine fingerprinting); however lack of immunogenicity means that it is not possible to confirm a secure negative with respect to respiratory sensitizing potential.