UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

(Rule 13d-102)

o

Rule 13d-1(b)

ý

Rule 13d-1(c)

o

Rule 13d-1(d)

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Citadel Limited Partnership

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

ý

(b)

o

3.

SEC Use Only

4.

Citizenship or Place of Organization
Illinois limited partnership

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
0

6.

Shared Voting Power 
6,022,723 shares

7.

Sole Dispositive Power 
0

8.

Shared Dispositive Power
See Row 6 above.

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
See Row 6 above.

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

11.

Percent of Class Represented by Amount in Row (9)
Approximately 5.4% as of the date of this filing

12.

Type of Reporting Person (See Instructions)
PN; HC

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Citadel Investment Group, L.L.C.

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

ý

(b)

o

3.

SEC Use Only

4.

Citizenship or Place of Organization
Delaware limited liability company

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
0

6.

Shared Voting Power 
6,022,723 shares

7.

Sole Dispositive Power 
0

8.

Shared Dispositive Power
See Row 6 above.

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
See Row 6 above.

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

11.

Percent of Class Represented by Amount in Row (9)
Approximately 5.4% as of the date of this filing

12.

Type of Reporting Person (See Instructions)
OO; HC

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Kenneth Griffin

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

ý

(b)

o

3.

SEC Use Only

4.

Citizenship or Place of Organization
U.S. Citizen

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
0

6.

Shared Voting Power 
6,022,723 shares

7.

Sole Dispositive Power 
0

8.

Shared Dispositive Power
See Row 6 above.

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
See Row 6 above.

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

11.

Percent of Class Represented by Amount in Row (9)
Approximately 5.4% as of the date of this filing

12.

Type of Reporting Person (See Instructions)
IN; HC

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Citadel Wellington LLC

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

ý

(b)

o

3.

SEC Use Only

4.

Citizenship or Place of Organization
Delaware limited liability company

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
0

6.

Shared Voting Power 
6,022,723 shares

7.

Sole Dispositive Power 
0

8.

Shared Dispositive Power
See Row 6 above.

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
See Row 6 above.

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

11.

Percent of Class Represented by Amount in Row (9)
Approximately 5.4% as of the date of this filing

12.

Type of Reporting Person (See Instructions)
OO; HC

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Citadel Kensington Global Strategies Fund Ltd.

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

ý

(b)

o

3.

SEC Use Only

4.

Citizenship or Place of Organization
Bermuda company

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
0

6.

Shared Voting Power 
6,022,723 shares

7.

Sole Dispositive Power 
0

8.

Shared Dispositive Power
See Row 6 above.

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
See Row 6 above.

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

11.

Percent of Class Represented by Amount in Row (9)
Approximately 5.4% as of the date of this filing

12.

Type of Reporting Person (See Instructions)
CO; HC

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Citadel Equity Fund Ltd.

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

ý

(b)

o

3.

SEC Use Only

4.

Citizenship or Place of Organization
Cayman Islands company

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
0

6.

Shared Voting Power 
6,022,723 shares

7.

Sole Dispositive Power 
0

8.

Shared Dispositive Power
See Row 6 above.

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
See Row 6 above.

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

11.

Percent of Class Represented by Amount in Row (9)
Approximately 5.4% as of the date of this filing

12.

Type of Reporting Person (See Instructions)
CO; HC

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Citadel Trading Group L.L.C.

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

ý

(b)

o

3.

SEC Use Only

4.

Citizenship or Place of Organization
Delaware limited liability company

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
0

6.

Shared Voting Power 
6,022,723 shares

7.

Sole Dispositive Power 
0

8.

Shared Dispositive Power
See Row 6 above.

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
See Row 6 above.

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

11.

Percent of Class Represented by Amount in Row (9)
Approximately 5.4% as of the date of this filing

12.

Type of Reporting Person (See Instructions)
OO; BD

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Aragon Investments, Ltd.

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

ý

(b)

o

3.

SEC Use Only

4.

Citizenship or Place of Organization
Bermuda company

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
0

6.

Shared Voting Power 
6,022,723 shares

7.

Sole Dispositive Power 
0

8.

Shared Dispositive Power
See Row 6 above.

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
See Row 6 above.

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

11.

Percent of Class Represented by Amount in Row (9)
Approximately 5.4% as of the date of this filing

12.

Type of Reporting Person (See Instructions)
CO; BD

1.

Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)
Citadel Derivatives Group LLC

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

ý

(b)

o

3.

SEC Use Only

4.

Citizenship or Place of Organization
Delaware limited liability company

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
0

6.

Shared Voting Power 
6,022,723 shares

7.

Sole Dispositive Power 
0

8.

Shared Dispositive Power
See Row 6 above.

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
See Row 6 above.

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

11.

Percent of Class Represented by Amount in Row (9)
Approximately 5.4% as of the date of this filing

12.

Type of Reporting Person (See Instructions)
OO; BD

Item 1.

(a)

Name of Issuer
PROTEIN DESIGN LABS, INC.

(b)

Address of Issuer’s Principal Executive Offices
34801 Campus Drive
Fremont, CA 94555

Item 2.

(a)

Name of Person Filing

(b)

Address of Principal Business Office or, if none, Residence

(c)

Citizenship

Citadel Limited Partnership
131 S. Dearborn Street
32nd Floor
Chicago, Illinois 60603
Illinois limited partnership

Citadel Investment Group, L.L.C.
131 S. Dearborn Street
32nd Floor
Chicago, Illinois 60603
Delaware limited liability company

Kenneth Griffin
131 S. Dearborn Street
32nd Floor
Chicago, Illinois 60603
U.S. Citizen

Citadel Wellington LLC
c/o Citadel Investment Group, L.L.C.
131 S. Dearborn Street
32nd Floor
Chicago, Illinois 60603
Delaware limited liability company

Citadel Kensington Global Strategies Fund Ltd.
c/o Citadel Investment Group, L.L.C.
131 S. Dearborn Street
32nd Floor
Chicago, Illinois 60603
Bermuda company

Citadel Equity Fund Ltd.
c/o Citadel Investment Group, L.L.C.
131 S. Dearborn Street
32nd Floor
Chicago, Illinois 60603
Cayman Islands company

Citadel Trading Group L.L.C.
c/o Citadel Investment Group, L.L.C.
131 S. Dearborn Street
32nd Floor
Chicago, Illinois 60603
Delaware limited liability company

Aragon Investments, Ltd.
c/o Citadel Investment Group, L.L.C.
131 S. Dearborn Street
32nd Floor
Chicago, Illinois 60603
Bermuda company

Citadel Derivatives Group LLC
c/o Citadel Investment Group, L.L.C.
131 S. Dearborn Street
32nd Floor
Chicago, Illinois 60603
Delaware limited liability company

(d)

Title of Class of Securities
Common Stock, par value $0.01 per share

(e)

CUSIP Number
74369L103

Item 3.

If this statement is filed pursuant to §§240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

(a)

o

Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).

(b)

o

Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).

(c)

o

Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).

(d)

o

Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C 80a-8).

(e)

o

An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);

(f)

o

An employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F);

(g)

o

A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);

(h)

o

A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i)

o

A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j)

o

Group, in accordance with §240.13d-1(b)(1)(ii)(J).

If this statement is filed pursuant to Rule 13d-1(c), check this box.  ý

Item 4.

Ownership

Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

CITADEL LIMITED PARTNERSHIP
CITADEL INVESTMENT GROUP, L.L.C.
KENNETH GRIFFIN
CITADEL WELLINGTON LLC
CITADEL KENSINGTON GLOBAL STRATEGIES FUND LTD.
CITADEL EQUITY FUND LTD.
CITADEL TRADING GROUP L.L.C.
ARAGON INVESTMENTS, LTD.
CITADEL DERIVATIVES GROUP LLC

(a)

Amount beneficially owned:   

6,022,723 shares

(b)

Percent of class:   

Approximately 5.4% as of the date of this filing

(c)

Number of shares as to which the person has:

(i)

Sole power to vote or to direct the vote   

0

(ii)

Shared power to vote or to direct the vote    

See Item 4(a) above.

(iii)

Sole power to dispose or to direct the disposition of   

0

(iv)

Shared power to dispose or to direct the disposition of   

See Item 4(a) above.

Item 5.

Ownership of Five Percent or Less of a Class

Not Applicable.

Item 6.

Ownership of More than Five Percent on Behalf of Another Person

Not Applicable.

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person

See Item 2 above.

Item 8.

Identification and Classification of Members of the Group

Not Applicable.

Item 9.

Notice of Dissolution of Group

Not Applicable.

Item 10.

Certification

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

* Mathew B. Hinerfeld is signing on behalf of Kenneth Griffin as attorney-in-fact pursuant to a power of attorney previously filed with the Securities and Exchange Commission on February 4, 2005, and hereby incorporated by reference herein.  The power of attorney was filed as an attachment to a filing by Citadel Limited Partnership on Schedule 13G/A for Komag, Incorporated.

KENNETH GRIFFIN

CITADEL KENSINGTON GLOBAL

STRATEGIES FUND LTD.

By:

/s/ Matthew B. Hinerfeld

Matthew B. Hinerfeld, attorney-in-fact*

By:

Citadel Limited Partnership,

its Portfolio Manager

CITADEL INVESTMENT GROUP, L.L.C.

By:

Citadel Investment Group, L.L.C.,

By:

/s/ Matthew B. Hinerfeld

its General Partner

Matthew B. Hinerfeld, Managing

Director and Deputy General Counsel

By:

/s/ Matthew B. Hinerfeld

Matthew B. Hinerfeld, Managing

CITADEL LIMITED PARTNERSHIP

Director and Deputy General Counsel

By:

Citadel Investment Group, L.L.C.,

CITADEL EQUITY FUND LTD.

its General Partner

By:

Citadel Limited Partnership,

By:

/s/ Matthew B. Hinerfeld

its Portfolio Manager

Matthew B. Hinerfeld, Managing

Director and Deputy General Counsel

By:

Citadel Investment Group, L.L.C.,

its General Partner

CITADEL WELLINGTON LLC

By:

/s/ Matthew B. Hinerfeld

By:

Citadel Limited Partnership,

Matthew B. Hinerfeld, Managing

its Managing Member

Director and Deputy General Counsel

By:

Citadel Investment Group, L.L.C.,

CITADEL TRADING GROUP L.L.C.

its General Partner

By:

Citadel Limited Partnership,

By:

/s/ Matthew B. Hinerfeld

its Managing Member

Matthew B. Hinerfeld, Managing

Director and Deputy General Counsel

By:

Citadel Investment Group, L.L.C.,

its General Partner

By:

/s/ Matthew B. Hinerfeld

Matthew B. Hinerfeld, Managing

Director and Deputy General Counsel

ARAGON INVESTMENTS, LTD.

By:

Citadel Limited Partnership,

its Portfolio Manager

By:

Citadel Investment Group, L.L.C.,

its General Partner

By:

/s/ Matthew B. Hinerfeld

Matthew B. Hinerfeld, Managing

Director and Deputy General Counsel

CITADEL DERIVATIVES GROUP LLC

By:

Citadel Limited Partnership,

its Managing Member

By:

Citadel Investment Group, L.L.C.,

its General Partner

By:

/s/ Matthew B. Hinerfeld

Matthew B. Hinerfeld, Managing

Director and Deputy General Counsel