<PAGE>
 
                                 EXHIBIT 10.6

                                   EXHIBIT G


                               ESCROW AGREEMENT

     THIS ESCROW AGREEMENT (this "Agreement") is dated as of December 3, 1997,
by and among the undersigned Buyer (the "Buyer"), INTERCELL CORPORATION, a
corporation organized under the laws of the State of Colorado, U.S.A. (the
"Company"), and H. GLENN BAGWELL, JR., a duly licensed attorney who practices
law in the State of North Carolina, U.S.A., as Escrow Agent (the "Escrow
Agent").

     Capitalized terms used herein and not otherwise defined herein shall have
the meanings set forth in that Securities Purchase Agreement between the Company
and the Buyer dated as of December 3, 1997 (the "Securities Purchase
Agreement").

                             W I T N E S S E T H:

     WHEREAS, the Buyer and the Company have entered into the Securities
Purchase Agreement, pursuant to which the Company has agreed to sell, and the
Buyer has agreed to purchase, in two (2) separate closings as described in the
Securities Purchase Agreement, at the First Closing, the A-1 Debenture and the
Warrants (the "First Closing Securities"); and at the Second Closing, the A-2
Debenture, the Stock and the Sigma Stock (all of which as defined in the
Securities Purchase Agreement) (the "Second Closing Securities," and
collectively with the First Closing Securities, the "Securities"); and

     WHEREAS, the Buyer and the Company have agreed to effectuate the Closings
utilizing an escrow arrangement as described in this Agreement; and

     WHEREAS, it is a condition of the Company's obligation to sell, and the
Buyer's obligation to purchase, the Securities, that this Agreement be executed
and delivered; and

     WHEREAS, the Escrow Agent is willing to act hereunder on the terms and
conditions set forth herein;

     NOW, THEREFORE, in consideration of the mutual covenants and obligations
set forth below, the parties hereto hereby agree as follows:

     1.   ESCROW ACCOUNT.

     1.1  Deposit.  On the date of the First Closing, Buyer shall deposit the
          -------                                                            
First Closing Purchase Price, and on the date of the Second Closing, Buyer shall
deposit the Second Closing Purchase Price (collectively, the "Escrow") with the
Escrow Agent, to be held by the Escrow Agent in a separate non-interest bearing
account (the "Escrow Account"), established at Wachovia Bank of North Carolina,
N.A., (the "Bank"), subject to the terms and provisions contained herein. At the
request of the Company the Escrow Agent shall provide the Company with all Bank
statements, notices and other writings which it receives from the Bank in
connection with the Escrow Account.

                                       1
<PAGE>
 
     1.2  Transfer of Escrow Account.  The Company may at any time hereafter
          --------------------------                                        
request by notice to the Escrow Agent that the Escrow Account be transferred to
another banking institution. In such event, the Escrow Agent shall, within two
(2) business days after receiving such notice, transfer the remaining Escrow as
the Company may instruct, whereupon the transferee banking institution shall
become the "Bank" for purposes of this Agreement and the account into which the
remaining Escrow is deposited shall become the "Escrow Account", in all cases
subject to this Agreement.

     2.   DISBURSEMENT OF ESCROW/SECURITIES.

     2.1  Disbursement.  At each Closing, upon receipt by the Escrow Agent of
          ------------                                                       
all of the moneys, documents, and things from the respective parties with
respect to such Closing as described in the Securities Purchase Agreement and as
further described in Sections 2.1(a) and 2.1(b) below, the Escrow Agent shall
deliver to each party via facsimile the documents and things (or if requested by
the parties, only the signature pages thereto) to have been delivered by the
other party in accordance with the Securities Purchase Agreement and this
Agreement. The Escrow Agent shall promptly wire transfer to the Company the full
Escrow then held, less any charges and fees agreed to be paid by the Company.
The Escrow Agent shall, upon receipt thereof, deliver (via overnight delivery
service) to the Company originals of all other documents and things listed in
Section 2.1(b) below. The Escrow Agent shall, upon receipt thereof, deliver (via
overnight delivery service) originals of all of the documents and things listed
in Section 2.1(a) below to the Buyer at the address provided in writing by the
Buyer to the Escrow Agent.

     The Closings may take place via facsimile. This shall be accomplished in
the following manner. Each party shall deliver via facsimile to the Escrow
Agent, at the telecopier number provided on the signature page to this
Agreement, the first page and the fully executed signature page to each of the
documents and things to be executed by such party at the applicable Closing. If
stock certificates are to be delivered, each such certificate shall be delivered
via facsimile to the Escrow Agent. Upon receipt of the requisite documents and
things via facsimile from each party, the Escrow Agent shall in turn send to
each party the documents and things received from the other party, and shall
wire transfer the Escrow (less any charges and fees agreed to be paid by the
Company). Each party closing the transactions contemplated herein via facsimile
shall deliver via overnight courier service to the Escrow Agent complete
originals of all documents and things (as called for in Sections 2.1(a) and
2.1(b) below) within one (1) business day after such delivery via facsimile.
Each party hereby agrees that a facsimile of each document and thing to be
delivered hereunder, once delivered to the Escrow Agent, shall be binding upon
such party in the same manner as would an original to the full extent allowed by
applicable law.

     (a). Items to be Delivered by the Company to the Escrow Agent.
          -------------------------------------------------------- 

     (i)  At the First Closing.  On the date of the First Closing, the Company
          --------------------                                                
shall deliver to the Escrow Agent on behalf of the Buyer, unless otherwise
stated, two (2) fully executed (by the authorized officer(s) of the Company)
originals of each of the following documents: (I) the Securities Purchase
Agreement, (II) the Registration Rights Agreement of even date herewith between
the Company and the Buyer, (III) the fully executed A-1 Debenture along with one
(1) copy of the fully executed A-1 Debenture; (IV) the fully executed Warrant #1
along with one (1) copy of Warrant #1; (V) the fully executed Warrant #2 along
with one (1) copy of Warrant #2;

                                       2
<PAGE>
 
(VI) the fully executed Warrant #3 along with one (1) copy of Warrant #3; and
(VII) this Agreement.

     (ii) At the Second Closing.  On the date of the Second Closing, the Company
          ---------------------                                                 
shall deliver to the Escrow Agent on behalf of the Buyer, one (1) fully executed
(by the authorized officer(s) of the Company) original and one (1) copy of each
of the following documents: (I) the fully executed A-1 Debenture; (II) a
certificate or certificates representing the Sigma Stock; and (III) a
certificate or certificates representing the Stock.

     (a)  Items to be Delivered by the Buyer to the Escrow Agent.
          ------------------------------------------------------ 

     (i)  At the First Closing.  On the date of the First Closing, the Buyer
          --------------------                                              
shall deliver to the Escrow Agent on behalf of the Company, unless otherwise
stated, two (2) fully executed originals of each of the following documents: (I)
the Securities Purchase Agreement, (II) the Registration Rights Agreement of
even date herewith between the Company and the Buyer, (III) this Agreement; and
(IV) the First Closing Purchase Price via wire transfer to the Escrow Account.

     (ii) At the Second Closing.  On the date of the Second Closing, the Buyer
          ---------------------                                               
shall deliver to the Escrow Agent the Second Closing Purchase Price via wire
transfer to the Escrow Account.

     2.2  Controversies.  If any controversy arises between two or more of the
          -------------                                                       
parties hereto, or between any of the parties hereto and any person not a party
hereto, as to whether or not or to whom the Escrow Agent shall deliver the
Escrow or any portion thereof or as to any other matter arising out of or
relating to this Escrow Agreement, the Escrow Agent shall not be required to
determine the same and need not make any delivery of the Escrow concerned or any
portion thereof but may retain the same until the rights of the parties to the
dispute shall have been finally determined by agreement or by final judgment of
a court of competent jurisdiction after all appeals have been finally determined
(or the time for further appeals has expired without an appeal having been
made). The Escrow Agent shall deliver that portion of the Escrow concerned
covered by such agreement or final order within five (5) days after the Escrow
Agent receives a copy thereof. The Escrow Agent shall assume that no such
controversy has arisen unless and until it receives written notice from the
Buyer or the Company that such controversy has arisen, which refers specifically
to this Agreement and identifies the adverse claimants to the controversy.

     2.3  No Other Disbursements.  No portion of the Escrow monies shall be
          ----------------------                                           
disbursed or otherwise transferred except in accordance with this Section 2,
Section 4 or Section 5.1(b).  Without limiting the foregoing, neither Escrow
Agent nor the Buyer shall be entitled to any right of offset against the Escrow
or otherwise entitled to receive any portion of the Escrow.

     3.   ESCROW AGENT.  The acceptance by the Escrow Agent of his duties
hereunder is subject to the following terms and conditions, which the parties to
this Agreement hereby agree shall govern and control with respect to the rights,
duties, liabilities and immunities of the Escrow Agent:

                                       3
<PAGE>
 
     3.1  The Escrow Agent shall not be responsible or liable in any manner
whatever for the sufficiency, correctness, genuineness or validity of any cash,
investments or other amounts deposited with or held by it.

     3.2  The Escrow Agent shall be protected in acting upon any written notice,
certificate, instruction, request or other paper or document believed by it to
be genuine and to have been signed or presented by the proper party or parties.

     3.3  The Escrow Agent shall not be liable for any act done hereunder except
in the case of its gross negligence, willful misconduct or bad faith.

     3.4  The Escrow Agent shall not be obligated or permitted to investigate
the correctness or accuracy of any document or to determine whether or not the
signatures contained in said documents are genuine or to require documentation
or evidence substantiating any such document or signature.

     3.5  The Escrow Agent shall have no duties as Escrow Agent except those
which are expressly set forth herein, and in any modification or amendment
hereof; provided, however, that no such modification or amendment hereof shall
affect its duties unless it shall have given its written consent thereto. The
Escrow Agent shall not be prohibited from owning an equitable interest in the
Company, any of its subsidiaries or any third party that is in any way
affiliated with or conducts business with the Company.

     3.6  The Company and the Buyer specifically acknowledge that the Escrow
Agent is an officer and shareholder in the Global Funding Group, a North
Carolina investment banking firm under contract with the Company with respect to
the transactions contemplated herein and in the Securities Purchase Agreement,
and which has worked with affiliates of the Buyer (along with the Escrow Agent)
on other unrelated transactions, and that they and each of them has specifically
requested that the Escrow Agent draft the documentation for the said
transactions and act as Escrow Agent with respect to the said transactions.
Each party represents that it has retained legal and other counsel of its
choosing with respect to the transactions contemplated herein and in the
Securities Purchase Agreement, and is satisfied in its sole discretion with the
form and content of the documentation drafted by the Escrow Agent. The said
parties hereby waive any objection to the Escrow Agent so acting based upon
conflict of interest or lack of impartiality. The Escrow Agent agrees to act
impartially and in accordance with the terms of this Agreement and with the
parties' respective instructions, so long as they are not in conflict with the
terms of this Agreement.

     4.   TERMINATION.  This Agreement shall terminate on the earlier of (a) the
date on which the Escrow and all other escrowed documents and things described
herein shall have been fully disbursed in accordance with the terms and
conditions of this Agreement, and (b) any other date agreed to by the Buyer and
the Company, in which event the Escrow shall be disbursed in full to the
Company.

                                       4
<PAGE>
 
     5.   MISCELLANEOUS.

     5.1  Indemnification of Escrow Agent.
          ------------------------------- 

     (a)  The Company and the Buyer each agree, jointly and severally, to
indemnify the Escrow Agent for, and to hold him harmless against, any loss
incurred without gross negligence, willful misconduct or bad faith on the Escrow
Agent's part, arising out of or in connection with the administration of this
Agreement, including the costs and expenses of defending himself against any
claim or liability in connection with the exercise or performance of any of its
powers or duties hereunder. This indemnification shall not apply to a party with
respect to a direct claim against the Escrow Agent by such party alleging in
good faith a breach of this Agreement, which claim results in a final non-
appealable judgment against the Escrow Agent with respect to such claim.

     (b)  In the event of any dispute as to the nature of the rights or
obligations of the Buyer, the Company or the Escrow Agent hereunder, the Escrow
Agent may at any time or from time to time interplead, deposit and/or pay all or
any part of the Escrow Funds with or to a court of competent jurisdiction
sitting in Wake County, North Carolina or in any appropriate federal court, in
accordance with the procedural rules thereof. The Escrow Agent shall give notice
of such action to the Company and the Buyer. Upon such interpleader, deposit or
payment, the Escrow Agent shall immediately and automatically be relieved and
discharged from all further obligations and responsibilities hereunder,
including the decision to interplead, deposit or pay such funds.

     5.2  Amendments.  This Agreement may be modified or amended only by a
          ----------                                                      
written instrument executed by each of the parties hereto.

     5.3  Notices.  All communications required or permitted to be given under
          -------                                                             
this Agreement to any party hereto shall be sent by first class mail or
facsimile to such party at the address, except in the case of the Escrow Agent,
of such party set forth in the Securities Purchase Agreement and, in the case of
the Escrow Agent, at 3005 Anderson Drive, Suite 204, Raleigh, North Carolina
U.S.A. 27609.

     5.5  Successors and Assigns.  This Agreement shall bind and inure to the
          ----------------------                                             
benefit of the parties hereto and their respective successors and assigns;
provided, however, that the Escrow Agent shall not assign its duties under this
Agreement.

     5.6  Governing Law.  This Agreement shall be governed by and construed and
          -------------                                                        
interpreted in accordance with the laws of the State of North Carolina.

     5.7  Counterparts.  This Agreement may be executed in two or more
          ------------                                                
counterparts, each of which shall be an original, and all of which together
shall constitute one and the same agreement.

IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the
day and year first above written.


                           [SIGNATURE PAGE FOLLOWS]

                                       5
<PAGE>
 
          [SIGNATURE PAGE TO ESCROW AGREEMENT DATED DECEMBER 3, 1997]



                                THE COMPANY:

                                INTERCELL CORPORATION


                                By /s/ Paul H. Metzinger
                                  -----------------------------------------
                                   Mr. Paul H. Metzinger, President & CEO



                                THE BUYER:

                                THE AUGUSTINE FUND, L.P.

                                By: Augustine Capital Management, Inc.

                                By /s/ Thomas F. Duszinski
                                  -------------------------
                                       Thomas F. Duszinski, Chief Operating 
                                       Officer 


                                ESCROW AGENT:

                                 /s/ H. Glenn Bagwell, Jr.
                                ---------------------------
                                H. Glenn Bagwell, Jr., Esq.

                                Address:

                                3005 Anderson Drive, Suite 204
                                Raleigh, North Carolina USA 27609 
                                Telephone: 919-785-3113           
                                Telecopier: 919-785-3116           

 

                                       6