SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, DC 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER
PURSUANT TO RULE 13a-16 OR 15d-16 OF
THE SECURITIES EXCHANGE ACT OF 1934

30 June, 2006

Cambridge Antibody Technology Group PLC
(Translation of Registrant’s Name Into English)

Milstein Building, Granta Park, Cambridge, CB1 6GH, England
(Address of Principal Executive Offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-

Form 20-F ____X____ Form 40-F ________

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):

Indicate by check mark whether by furnishing the information contained in this Form, the registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2 (b) under the Securities Exchange Act of 193

Yes _________ No ____X_____

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2 (b): 82-___________

EXHIBIT INDEX

This filing contains the following exhibits.

EXHIBIT DESCRIPTION

99.1 Holding(s) in Company dated 30 June 2006

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: 30 June, 2006 Cambridge Antibody Technology Group PLC

                                                                                                                                                                 By: /s/ John Aston
                                                                                                                                                                 Name: John Aston
                                                                                                                                                                 Title: Chief Financial Officer

EXHIBIT 99.1

                   NOTIFICATION OF MAJOR INTERESTS IN SHARES



1. Name of company



CAMBRIDGE ANTIBODY TECHNOLOGY GROUP PLC



2. Name of shareholder having a major interest



ASTRAZENECA UK LIMITED



3. Please state whether notification indicates that it is in respect of holding
of the shareholder named in 2 above or in respect of a non-beneficial interest
or in the case of an individual holder if it is a holding of that person's
spouse or children under the age of 18



ASTRAZENECA UK LIMITED       NOT DISCLOSED



4. Name of the registered holder(s) and, if more than one holder, the number of
shares held by each of them


15,817,983      ASTRAZENECA UK LIMITED
178,607         GREENWOOD NOMINEES LIMITED
11,962          DR PAUL NICHOLSON


32,109,070      REPRESENTING ACCEPTANCES OF THE OFFER AND RECENT
                PURCHASES TO BE REGISTERED IN THE NAME OF ASTRAZENECA UK LIMITED




5. Number of shares / amount of stock acquired



15,917,983



6. Percentage of issued class



29.92%



7. Number of shares / amount of stock disposed



N/A



8. Percentage of issued class



N/A



9. Class of security



ORDINARY 10 PENCE SHARES



10. Date of transaction



NOT DISCLOSED

11. Date company informed



29 JUNE 2006



12. Total holding following this notification



48,117,622



13. Total percentage holding of issued class following this notification



90.44%



14. Any additional information



NONE



15. Name of contact and telephone number for queries



JUSTIN HOSKINS 01223 898589



16. Name and signature of authorised company official responsible for making
this notification



JUSTIN HOSKINS, COMPANY SECRETARY



Date of notification



30 JUNE 2006



The FSA does not give any express or implied warranty as to the accuracy of this
document or material and does not accept any liability for error or omission.
The FSA is not liable for any damages (including, without limitation, damages
for loss of business or loss of profits) arising in contract, tort or otherwise
from the use of or inability to use this document, or any material contained in
it, or from any action or decision taken as a result of using this document or
any such material.

CAMBRIDGE ANTIBODY TECHNOLOGY GROUP PLC 6-K